ArticlePDF Available

Reactor accident chemistry an update

March 2018
Cogent Chemistry 4(1)

March 2018
4(1)

DOI:10.1080/23312009.2018.1450944

License
CC BY 4.0

Authors:

Mark Foreman

Chalmers University of Technology

A review and discussion of some of the literature on the subject of serious nuclear reactor accidents. This review addresses some biological issues such as the influence of dose rate on the ability of radiation to cause harm, the chemistry of a selection of serious accidents and the behaviour of a series of important fission products and the actinides. This review is intended for scientists with a professional interest in nuclear reactors, chemists in general and I expect that it will be of use to historians with an interest in the nuclear industry and its relationship with wider society.

Available via license: CC BY 4.0

Content may be subject to copyright.

Full Terms & Conditions of access and use can be found at

https://www.tandfonline.com/action/journalInformation?journalCode=oach20

Cogent Chemistry

ISSN: (Print) 2331-2009 (Online) Journal homepage: https://www.tandfonline.com/loi/oach20

Reactor accident chemistry an update

Mark R. St J. Foreman |

To cite this article: Mark R. St J. Foreman | (2018) Reactor accident chemistry an update, Cogent

Chemistry, 4:1, 1450944, DOI: 10.1080/23312009.2018.1450944

To link to this article: https://doi.org/10.1080/23312009.2018.1450944

article is distributed under a Creative

Commons Attribution (CC-BY) 4.0 license.

Published online: 28 May 2018.

Submit your article to this journal

Article views: 1383

View related articles

View Crossmark data

Citing articles: 2 View citing articles

INORGANIC CHEMISTRY | REVIEW ARTICLE

Reactor accident chemistry an update

Mark R. St J. Foreman

Abstract: A review and discussion of some of the literature on the subject of serious

nuclear reactor accidents. This review addresses some biological issues such as the

influence of dose rate on the ability of radiation to cause harm, the chemistry of a

selection of serious accidents and the behaviour of a series of important fission

products and the actinides. This review is intended for scientists with a professional

interest in nuclear reactors, chemists in general and I expect that it will be of use to

historians with an interest in the nuclear industry and its relationship with wider

society.

Subjects: Applied & Industrial Chemistry; Environmental Chemistry; Nuclear Engineering;

Energy & Fuels

Keywords: nuclear reactors; nuclear accidents; radiation; fission products; nuclear fuel;

cesium; nuclear power; radioactivity

1. Introduction

The use of nuclear energy for the production of electricity is a divisive matter, it is clear that

“nuclear power”is a polarizing topic. One of the great problems of our age is the supply of energy

for industrial and household purposes, in her book Clare Smallman pointed out that modern

humans use far more energy than that is required for their bodies to function (Smallman, 1981).

While a return to a more primitive way of living might offer a means of reducing our energy use, it

is a lifestyle change which few people want to undertake. It is important to consider both the

energy which is delivered to our homes and vehicles as well as the energy required by industry to

produce the products which many of us use and consume. For example, aluminium metal requires

ABOUT THE AUTHOR

The author is a chemist who has a professional

interest in the phenomena associated with

radiological accidents. He has worked with

other scientists to better understand these

events and to try to reduce their ability to

harm the general public. In recent times he

has performed research considering how

trustworthy respiratory protection and iodine

sampling devices based on charcoals are. He

has been working recently with Aldo Jesorka

on miniature devices designed to assist in the

sampling and measurement of radioactivity

during serious radiological accidents. Both

these projects were funded by the Swedish

radiation protection authority (SSM).

Additionally Mark has academic interests in

recycling, solvent extraction, novel solvents

and other areas.

PUBLIC INTEREST STATEMENT

Radiation and nuclear accidents are of great interest

to the general public, the great concern relates in

part to the fact that radiation cannot be observed

with a human bodies senses. It is likely that the

inability to see/hear/feel/smell or taste the threat

coupled with the comparative novelty of radiologi-

cal accidents does heighten the degree of concern.

As I wish to see nuclear/radioactive issues discussed

honestly with arguments based on facts rather than

feelings, half-truths and even complete fabrications

I have chosen to write a large review of the phe-

nomena (mainly chemical) associated with serious

accidents. I wanted to write a review which would

be of use to scientists, both supporters and oppo-

nents of “nuclear power”, future historians of the

nuclear age and interested members of the general

public. By providing others with better access to the

truth and explaining some matters I want to

improve the way in which nuclear technology is

discussed in society.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Attribution (CC-BY) 4.0 license.

Received: 21 February 2018

Accepted: 27 February 2018

First Published: 13 March 2018

*Corresponding author: Mark R. St J.

Foreman, Industrial Materials

Recycling, Department of Chemistry

and Chemical Engineering, Chalmers

University of Technology, Göteborg,

Sweden

E-mail: Foreman@chalmers.se

Reviewing editor:

Alexandra Martha Zoya Slawin,

University of St. Andrews, United

Kingdom

Additional information is available at

the end of the article

Page 1 of 100

a very large amount of energy to produce. Nuclear power offers a low carbon alternative to coal as

an energy source; however, the waste is the subject of considerable concern by the public, pressure

groups and governments. Additionally the consequences of accidents at nuclear sites is of great

concern, the problem of a “nuclear accident”is one of the barriers to widespread use of nuclear

technology in some parts of the world. After a radiological accident two pathways for exposure

exist, firstly radioactivity can be scattered over surfaces. The radiation from contaminated surfaces

and sometimes from a passing cloud of radioactivity can expose people to radiation, even without

need for a person to inhale, swallow or otherwise incorporate radioactivity into their body. For

many radioisotopes it is relatively easy to calculate the exposure for a person standing on an

infinite area of flat land which is uniformly contaminated using conversion factors such as those of

Beck (1980). One great problem is making a good estimate or measurement of the contamination

level (Bq m

−2

) and also very few people spend their time on a perfectly flat uniformly contaminated

surface of land. The other type of exposure scenario is one in which a person absorbs radioactivity

and then undergoes internal exposure. The internal exposure cases are often more complex than

the external exposures.

Sadly I am unable to review all radiological misadventures, in order to create a review paper

which can be read a need exists to exclude some events. I have chosen to exclude most of the

sealed source accidents which have occurred all too frequently in industrial radiography and

radiotherapy. In many ways these smaller accidents tend to be more deadly than nuclear power

reactor accidents, while these accidents have caused more deaths and injuries due to acute effects

among the general public than events such as the Windscale fire, Three Mile Island, Chernobyl and

Fukushima I suspect that these accidents are less able to capture the attention of the public. A

good review (Coy et al., 1998) of such events already exists which reduces the need for me to write

about them. I would like to warn my reader to be careful of what you look at and what you search

for, some things cannot be unseen. Some radiographic accidents such as the lost 30 Ci

192

Ir source

accident in Morocco (1984) which killed eight members of a family are to me the radiological

equivalent to a horror film. I will not be showing shocking photographs of radiation injuries or

including graphic descriptions of horrible injuries. I have also chosen to exclude the majority of

events where a deliberate or reckless exposure of people to radiation has occurred. Thus I will not

be discussing “radiological assault”, nuclear warfare or nuclear bomb tests in length. One major

reason is that these events are not accidents, but occasionally these events will be discussed when

an accident occurred during a planned nuclear or radiological event. For example during one

hydrogen bomb test due to an incorrect assumption the yield of the bomb was far greater than

expected.

By providing this review and my earlier review (Foreman, 2015) I hope that knowledge and

reasoned thought on this subject will be of some use to both specialists within the radioactivity

and nuclear sectors, other scientists and members of the public. Rather than make a simple list of

papers on the subject (Bujdosó, 1987) I have chosen where possible to discuss the sources which I

have found in the literature. In the ideal world men and women would reason clearly and discuss

all manner of topics in a civil and honest manner, but sadly this utopia has not come to be. Instead

we live in an age where falsehoods are sometimes deliberately propagated, where through

recklessness or carelessness incorrect information is disseminated and where all the horrible tricks

of bad argument documented by Thouless (1953) are being used. I hope that this review enlight-

ens the reader and makes life harder for those who for various reasons attempt to influence others

through misinformation on nuclear matters. I have wanted to write a document which is useful

both to the supports and the opponents of the nuclear industry. At times I have chosen to criticize

some organizations and persons for either recklessly or deliberately spreading falsehoods or for

other reasons, I want the reader of this review to understand such criticism is not ideologically

motivated. I disapprove equally of pro- and anti-nuclear campaigners who misbehave as described

above. I am sure that both those who read this review shortly after publication and those who read

it years and decades afterwards will be aware of the problems of “alternative facts”,“fake news”

and “the rejection of expert opinion in favour of that of the layperson”. I do not want to diverge too

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 2 of 100

far into the world of politics, but it will be clear to many of my readers that some political leaders

and other public figures are “economical with the truth”while others go beyond failing to tell the

whole truth by knowingly or recklessly disseminating falsehoods.

Some of my readers will be aware of a sorry tale from Soviet botany from the era when Josef

Stalin was the leader of the Union of Soviet Socialist Republics (USSR) of lysenkoism. The core of

this pseudoscience was that it is possible to train plants in much the same way as Pavlov and

Skinner trained dogs and other animals. Pavlov with his famous experiments with bells (and other

stimuli) and Skinner with his “Skinner Box”(operant conditioning chamber) trained animals. Part of

the problem was that Lysenko and Stalin indulged in violence and other forms of repression

against geneticists. In today’s society I see a disturbing parallel. I am aware of intimidation

campaigns being waged against scientists and other intellectuals who happen to be publishing

or expressing views which challenge the ideas, political agenda or economic activities of another

person (natural or otherwise). I will go quickly through some examples of this. Caroline Criado-

Perez the journalist along with Stella Creasy campaigned for more women to appear on Bank of

England banknotes, unfortunately they were subject to harassment in the form of menacing and

grossly offensive electronic communications. At least two people who threatened Caroline Criado-

Perez have been sent to prison (Cockerell, 2014). One case which is closer intellectually to the

subject of this paper is the tale of what happened to Jay Cullen. He is an academic who works on

the chemistry of the oceans, after the Fukushima event he measured the cesium content of sea

water and came to the conclusion that the radioactive cesium level in the water was too low to be

harmful. An activist named Dana Durnford issued death threats against Jay Cullen and another

academic, he has now been convicted in a criminal court case (Wanklyn, 2016). I imagine that the

vast majority of my readers are decent and moral people, but just in case you know someone who

is considering embarking on a campaign of harassment or intimidation then I would like to point

out that such a course of action can result in serious harmful consequences.

Before we go on, it is important to make something clear. Within this review the word “sig-

nificant”is used to indicate something which is statistically significant. As the UK’s health and

safety executive summed it up crisply my stating “statistical significance”should not be confused

with the significance of each injury. Every casualty is a tragedy and has both a social cost and a

personal cost to those “directly affected”. I have to admit that regardless of the statistical

significance any fatality, injury or loss of the use of land or other property is significant to those

affected.

In this review I will start by considering the question of how bad is radiation, before considering

the circumstances and chemistry of a selection of reactor accidents. After considering the resus-

pension of radioactivity I will consider the chemistry of a series of important radioactive elements

in turn. Sadly I am unable to make a totally comprehensive review, but I have attempted to write

about what I think are the most important and interesting issues.

2. Review

2.1. How dangerous is radiation

One can argue that ionizing radiation should be treated like a chemical poison as gamma rays,

beta particles, alpha particles and neutrons cause harm by delivering energy to water and other

substances inside the body thus forming reactive species which in turn damage biomolecules

including DNA. Debate rages over the question of “how harmful is radiation”.

It is important to note that the harmful effects of radiation to any population should not be

exaggerated regardless of how noble the purpose of the exaggeration is in the mind of the

exaggerator. One problem is that if risk is exaggerated then in an attempt to avoid one risk people

may be exposed to other (and greater risks). Secondly in the long run by exaggerating risk the

exaggerator and the cause that they represent may be discredited. Equally it would be deeply

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 3 of 100

wrong to deliberately downplay the harmful effects of radiation or radioactivity, again regardless

of how noble the purpose of the exaggeration is.

The mainstream scientific opinion on how harmful radiation is expressed by a series of

different bodies such as the ICRP (International Commission on Radiological Protection). When

considering other opinions is important to keep in mind the question of “who is expressing an

alternative view”and “what is the alternative view based on”. It is clear to me that radiological

protection and the creation of standards/dose limits is politically sensitive at times and can

become exceptionally controversial at times. In the popular media a range of ideas and alter-

native views are circulating. Some of these include claims that conspiracies exist to influence

radiation protection standards in a particular way to suit the interests of the “nuclear industry”.

For example it has been claimed by some that an agreement exists between the IAEA

(International Atomic Energy Authority) and the WHO (World Health Authority). Normally I

restrict myself to what is accepted by mainstream science, but occasionally I may mention

and discuss some of the alternative points of view on some issues when some valuable thing

can be learnt by considering them.

Regarding the accusation about the IAEA and the WHO, it relates to a 1959 agreement (WHA12-

40) between the two bodies. The text is rather long, it contains 13 articles. A selective reading

(cherry picking) of the agreement is required to come to the conclusion that the IAEA is able to

inhibit the WHO from an activity. The first article states in clause three.

“3. Whenever either organization proposes to initiate a program or activity on a subject in

which the other organization has or may have a substantial interest, the first party shall

consult the other with a view to adjusting the matter by mutual agreement.”

I have highlighted in bold the text which could be understood as meaning that the WHO can be

controlled by the IAEA. It is interesting to point out that clause 2 (as seen below) contains text

which indicates that the WHO recognizes that the IAEA has primary responsibility for nuclear

matters but the WHO still has the right to work on any aspect of health work.

“2. In particular, and in accordance with the Constitution of the World Health Organization

and the Statute of the International Atomic Energy Agency and its agreement with the

United Nations together with the exchange of letters related thereto, and taking into

account the respective co-ordinating responsibilities of both organizations, it is recognized

by the World Health Organization that the International Atomic Energy Agency has the

primary responsibility for encouraging, assisting and co- ordinating research and develop-

ment and practical application of atomic energy for peaceful uses throughout the world

without prejudice to the right of the World Health Organization to concern itself with

promoting, developing, assisting and co-ordinating international health work, including

research, in all its aspects.”

I hold the view that the agreement was a sensible choice in the 1950s for the two bodies to agree

to cooperate to prevent unnecessary duplication of work. The important message is when reading

a document such as statute it is important to read the whole of the document and judge it as a

whole rather than concentrating on a small part of the text. Similar misunderstandings can occur

as a result of cherry picking text from religious texts (such as the Bible), legal statutes or almost

any document. But now back to the chemistry, as we are mainly water we need to consider the

effect of radiation on water.

When water is subject to irradiation then a series of reactive species are formed. When pure

water is irradiated the solvated electron and the H

cation are formed. These then can recom-

bine to form an excited state of water (H

O*). The H

O* can then fragment forming neutral radicals

such as HO∙(hydroxyl radicals) and H∙(hydrogen atoms). The hydroxyl radicals and hydrogen

atoms can combine to form hydrogen peroxide, hydrogen gas and water.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 4 of 100

HOþHO! H2O2

HþH!H2

HþHO! H2O

A large number of rate constants have been measured for the reaction of the reactive species

formed by the irradiation of water (for example e

−

,HO∙and H∙) (Buxton, Greenstock, Helman, &

Ross, 1988). Often when water containing a solute is irradiated then the situation is more complex,

for example when oxygenated water is irradiated then the reducing radicals such as solvated

electrons and hydrogen atoms tend to react with the oxygen to form oxidizing radicals (Baxendale

& Smithies, 1956).

HþO2!HOO

The oxidizing radical can then react with biomolecules. The oxygen centred radicals can remove

(abstract) hydrogen atoms from organic species. The resulting carbon centred radicals can then

undergo a range of reactions.

This oxygen effect may be responsible for the fact that deoxygenated cancer cells are more

resistant to gamma rays and X-rays than oxygenated cancer cells. Often a tumour has an outer

layer which is well supplied with oxygen and nutrients, deeper within the tumour is an area which

is poorly supplied with oxygen and nutrients. Deeper still within the tumour is sometimes an area

of dead cells, cells which have died from a lack of oxygen and nutrients. If the oxygenated outer

layer of a tumour is killed by means of radiation then the less oxygenated cells (which may be in

suspended animation) can start to grow again. One solution to this oxygen effect is to use a high

LET (Linear Energy Transfer) radiation such as alpha particles (Tinganelli et al., 2015). With alpha

particles oxygen level has less effect on the ability of radiation to kill cells. The idea is to attach an

alpha emitter to a molecule which seeks a specific biological target. Another approach is to

administer a boron containing drug which preferentially absorbs into cancer cells, then to subject

the patient to neutron irradiation. The idea is that the neutrons will cause the boron to generate

alpha particles according to the following reaction.

10Bþn!7Li þ4He

Attempts are being made to create drugs containing boron (Bonjoch et al., 2008), one approach is

to attach polyhedral boron hydride groups to antibodies (Alam, Soloway, & Barth, 1987) or nucleo-

sides (Wojtczak, Andrysiak, Gruener, & Lesnikowski, 2008). Several reviews of boron neutron

capture therapy for cancer exist (Barth, Soloway, Fairchild, & Brugger, 1992; Nedunchezhian,

Aswath, Thiruppathy, & Thirugnanamurthy, 2016). The radicals such as HO∙can attack biomole-

cules (including DNA). This can lead to two things, if a large amount of damage is done in a short

time to the biomolecules of a cell then the cell may die. It is the death of cells in vital organs which

is responsible for the radiation injuries and deaths which have resulted from some accidental

radiation exposures. These acute effects of radiation are deterministic effects, the severity of the

clinical effects often are dependent on the radiation dose. This is similar to the fact that the effects

of alcoholic drinks on human behaviour often become more dramatic as the volume of alcohol

ingested increases.

When less damage is done to cells or when the damage occurs at a sufficiently low rate that the

self-repair mechanisms in the cells prevent the radiation killing the cells then the effect which

concerns us most is the modification of the DNA in the cells. It is impossible to argue that ionizing

radiation is incapable of inducing cancer, for example internal exposure to

Sr induces bone

cancer in dogs (Gillett, Pool, Taylor, Muggenburg, & Boecker, 1992) and it is interesting to note

that a Scottish industrial radiographer who had a lifetime whole body dose in the range of

10–15 Gy died of a form of leukaemia (acute myeloid) (Lloyd et al., 1994) which is a common

second cancer in cancer patients treated with radiotherapy. When the DNA is damaged sometimes

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 5 of 100

the cell will correctly repair it and sometimes during the attempt at repair the cell will fail to repair

it correctly. If we ignore cases where the DNA is so hopelessly damaged that the cell dies quickly,

we can have cells which have altered DNA which are able to continue to divide. A change of DNA is

known as a mutation. While feature films often contain “mutants”with a wide range of bizarre

appearances and abilities, a typical mutation will only make a less dramatic change. For example if

sufficient changes to the DNA of a cell occur then the normal cell will change in to a cancer cell. A

malignant cancer cell differs from a normal cell in three ways.

(1) The cell divides when it should not do so.

(2) The cell become immortal, instead of having a limited number of times it can divide it can

divide forever.

(3) The cell no longer respects the rules which govern where it should be in the body, a great

problem with cancer is that the primary tumour releases cells into the blood and lymph systems

which migrate to other parts of the body where they start dividing thus creating secondary

tumours. Often these secondary tumours are more dangerous than the primary tumour.

In contrast the acute effects of radiation the cancers induced by radiation do not become worse in

terms of symptoms or prognosis as the radiation dose which induced them becomes larger. The

only thing which becomes larger is the likelihood of developing a cancer. As the clinical course of a

radiation induced cancer is the same as that of a case of the same cancer induced by something

else it can be very difficult to prove that a given cancer case was induced by radiation. It is often

difficult to prove that an increase in the incidence of cancer in a population of humans is due to

the effect of radiation. When the incidence of an unusual cancer increases, such as either Kaposi

sarcoma or Clear-cell adenocarcinoma of the vagina in young people then the change is very

noticeable. These two cancers are noteworthy as the first helped to establish the existence of AIDS

while the second lead to the withdrawal of an artificial oestrogen drug (diethylstilbestrol) from the

market. While there are some cancers for which an association with radiation can be observed, for

many cancers it is harder to find a link.

We also have to ask the question of “should society outlaw a thing when it can be shown that it

might be linked to cancer?”. I hold the view that the answer should not automatically be yes, for

example some treatments for cancer are likely to have induced other cancers. The creation of one

cancer by a treatment which cures another might be a tolerable side effect for some people

(Pedersen-Bjergaard et al., 1981). By curing one cancer the cancer sufferer had their life extended.

Another example is a substance which many people choose to consume as a food (grapefruit). I am

aware that grapefruits are a key part of a weight (mass) loss diet which is known as the “Grapefruit

diet”(Hollywood diet). It is interesting that grapefruit consumption has been linked in a study of

50,000 postmenopausal women to an increase in the incidence of breast cancer (Monroe, Murphy,

Kolonel, & Pike, 2007). The study indicated that consumption of a quarter of a grapefruit per day

increases the relative risk of breast cancer by a factor of 1.3 (95% confidence interval of 1.06–1.58).

While this clearly indicates that eating grapefruits can have a harmful effect and despite the fact

that I loathe the taste of grapefruit I could not justify a ban on the importation, sale or consumption

of grapefruits. It is noteworthy that a European study of 114,504 women found no link between

grapefruit eating and breast cancer (Spencer et al., 2009). The reason why the grapefruit has been of

such interest is that it is known that this fruit (and St-John’s wort) can alter the behaviour of a range

of drugs (Mouly, Lloret-Linares, Sellier, Sene, & Bergmann, 2017), and it has been shown that

grapefruit juice containing naringenin, quercetin and kaempherol (flavonoids) inhibits the metabo-

lism of 17-beta-estradiol in women (Schubert, Cullberg, Edgar, & Hedner, 1994)(Figure 1).

While naringenin and quercetin are present in large amounts in grapefruit juice as these compounds

do not have an effect on the oral bioavailability of nifedipine, nisoldpine or felodipine (dimethyl-2,6-

dimethyl-4-(2,3-dichlorophenyl)-1,4-dihydropyridine-3,5-dicarboxylate). Tassaneeyakul, Guo, Fukuda,

Ohta, and Yamazoe (2000) disregarded them in their search for the substance which inhibits the

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 6 of 100

different forms of the P450 enzyme. Also it has been shown that the naringin and naringenin in

grapefruit juice is not responsible for its ability toinhibit the metabolism of testosterone by the CYP3A

version of P450 (Edwards & Bernier, 1996)(Figure2).

It has been shown in chemistry experiments by Tassaneeyakul et al. that furanocoumarins

present in grapefruit juice do have a great ability to inhibit the CYP1A2, CYP2C9, CYP2D6 and

CYP3A4 forms of the P450 enzyme. While these compounds might be present at lower concentra-

tions than naringenin in grapefruit juice they are far stronger inhibitors of the P450 enzymes. In

the paper by Tassaneeyakul et al. (2000), a series of compounds isolated from grapefruit juice such

as bergamottin, 6ʹ,7ʹ-dihydroxy bergamottin and two bis-furanocoumarins were identified as far

stronger inhibitors of these enzymes. These four compounds are likely to be the main inhibitors of

the P450 enzymes in grapefruit juice. It is reasoned that by inhibiting these enzymes in women

that their oestrogen level will rise, the increase in oestrogen will then favour the development of

breast cancer (Figure 3).

HO O

CH2OH

CH3

OH OH

Figure 1. Naringenin on the left

and naringin on the right.

COOCH3

H3COOC

NO2

COOCH3

NO2

Figure 2. Nifedipine (dimethyl

2,6-dimethyl-4-(2-nitrophenyl)-

1,4-dihydropyridine-3,5-dicar-

boxylate) and nisoldpine (3-

isobutyl 5-methyl 2,6-dimethyl-

4-(2-nitrophenyl)-1,4-dihydro-

pyridine-3,5-dicarboxylate).

Figure 3. Bergamottin.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 7 of 100

One might wonder why I have chosen to consider grapefruit in so much detail, the reason is that

it illustrates several things. Firstly there is the follies of inductive reasoning, inductive reasoning

works in the following way. We start with two of more statements which we believe are true, from

these we create a new statement. For example:

(1) Mark ate a stale prawn sandwich,

(2) The next day Mark was very ill.

The new statement or idea is “Eating stale prawn sandwiches can make you ill”. The problem

with this system of reasoning is that if one of the original statements is wrong then errors can

propagate forwards and corrupt our thinking. Also even if all the original statements are correct it

is possible to make an incorrect statement which might not be easily noticed as wrong. Consider

the following:

(1) A Geiger-Muller detector can detect fast moving electrons,

(2) Beta emitters are radionuclides which emit fast moving electrons.

Thus we can reason “Geiger-Muller detectors can be used to search for contamination with beta

emitters”. The only problem is that while GM tubes can detect beta emitters such as

P and

Sr/

Y they are unable to detect the lower energy beta particles from

H (tritium) and

Ni.

We can continue:

(1) Dr Foreman is an Englishman,

(2) Dr Foreman’s first name is Mark.

Thus “All Englishmen have the same first name (Mark)”

(1) Grapefruit inhibits P450 enzymes.

(2) Grapefruit contains naringenin.

Thus “Naringenin inhibits the P450 enzymes”.

Using inductive reasoning we have come up with three incorrect statements (one of which is

rather comical). A better system of doing science would be create a hypothesis (maybe using

inductive reasoning) and then to put the hypothesis to the test (an experiment designed to show if

it is not true). This is the falsificationist method in which one attempts to disprove a theory, the

more times one fails to disprove a theory the better and the more useful the theory becomes. The

theory that the GM detector is a universal detector for beta emitters can be tested by attempting

to measure a range of different beta emitters, the hypothesis regarding the universal first name of

Englishmen could be tested by asking 100 randomly chosen Englishmen their names while the

hypothesis that naringenin is the major P450 inhibitor in grapefruit was tested by Edwards and

others. I am sure that it will be possible with inductive reasoning to make some dire mistakes in

human radiation biology. One problem is that the study of an exposed group means little unless it

is compared with an unexposed group. The problem is that unless the right control group is chosen

then differences other than radiation exposure may cause both false positive and false negative

results. For example it would be of little use to compare men who worked at Sellafield in the 1970s

with women working in the 1980s in China as dentists. In this example, thankfully hypothetical, I

can see four differences between the populations. A better comparison was male radiologists and

male psychiatrists who worked in the USA. The most heavily exposed radiologists (graduated

before 1940) show an excess of deaths due to some forms of cancer, in particular melanoma (a

skin cancer), cancer of oesophagus and leukaemias other than chronic lymphocytic leukaemia

(CLL) (de González et al., 2016). When a population of male radiologists and psychiatrists who

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 8 of 100

graduated between 1960 and 1979 are compared their rates of melanoma, cancer of oesophagus

and leukaemias other than CLL. It can be reasoned that the main difference between the working

lives of the two types of medical doctor is that the radiologists tend to be radiation workers while

the psychiatrists do not work with radiation. The reduction of the difference between the two

populations as the year of graduation increases can be ascribed to the decrease in occupational

radiation exposure of the radiologists as work practices changed.

When people who took part in the British nuclear bomb tests in the 1950s were compared with

people who had experienced similar work but had not been present near the test sites during the

tests some differences can be observed. The population exposed to the tests included members of

the British military [army, navy and air force (RAF)] and workers from the atomic weapons research

establishment (AWRE). The AWRE was replaced by the atomic weapons establishment (AWE) and

the United Kingdom Atomic Energy Authority. The controls were members of the military who were

elsewhere in the world at the time of the tests but had served in the tropics (Kendall, Muirhead,

Darby, Doll, Arnold and O’Hagan, 2004). The population which had been exposed to the nuclear

weapon tests did have an excess of some forms of cancer (leukaemia and cancer of the liver,

bladder, prostrate and melanoma) (Muirhead et al., 2004).

The population in Japan who survived the two atomic bombings have been the subject of a large

number of scientific studies regarding the question of how harmful is radiation. In contrast to the

US doctors and the study on British atomic bomb veterans, in the work on the Hiroshima and

Nagasaki populations rather than being lumped into exposed and unexposed populations these

people have been divided up according to their dose estimates. Based on their locations at the

moment of detonation attempts have been made to reconstruct their doses. The incidence of solid

cancers in the survivors between 1958 and 2009 has been recently considered. In women the

excess relative risk (ERR) increased in a linear manner (0.64 per Gy), while for men the increase in

ERR is better modelled with a linear-quadratic (LQ) model (Grant et al., 2017). The different forms

of leukaemia appear to obey different mathematical models (Richardson et al., 2009).

For chronic myeloid leukaemia (CML) and acute lymphatic leukaemia (ALL) the ERR increases in a

linear manner as the dose in grays (D) increases according to the equation (β= 6.39 CML and

β=3.70ALL):

ERR DðÞ¼βD

For acute myeloid leukaemia (AML) the relationship between dose and ERR is different. As well as

the dose (D), the age of exposure and time since exposure all matter for this disease. The

expression for kis rather complex:

ERR DðÞ¼kD2

The younger a person is at the age of exposure the greater the risk of AML. This alone is a good

argument for setting a minimum age limit for radiation work. In the UK a person must be at least

16 to be allowed to do radiation work, until they reach the age of 18 they are restricted to a lower

annual dose limit to persons over 18. The BEIR VII committee were reported to have favoured a

ERR model for leukaemia which is given by the following equation:

ERR D;e;tðÞ¼βDþθD2



eγe0þδlog t

ðÞ

þϕe0log t

ðÞ½

The quadratic relationship between the cancer rate and the dose is interesting, it does conflict with

the linear no threshold (LNT) model which is commonly used. The LNT model is a key plank of the

argument that “collective dose”can be used to predict the number of cancer cases among the

general public or a group of workers after an exposure to radiation. If the LNT model is correct then it

would be reasonable to assume that 100 people exposed to 100 mSv each, 1,000 people exposed to

10 mSv each or 10,000 people exposed to 1 mSv each then the same number of cancer cases would

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 9 of 100

be induced. In all three cases I have used the collective dose would be 10 manSv. If a 1 Sv dose

increases the absolute lifetime risk of developing cancer by 5% then the 10 manSv dose would

induce 0.5 cancer cases. These cancer cases will be randomly distributed among the exposed

population. If the additional risk of cancer was proportional to the square of the dose or some

other non-linear mathematical function then the collective dose will be of little or no use.

In a very good book (Coggle, 1971) on radiation biology John Coggle mentioned that different

bacteria have different graphs of log (surviving fraction; SF) vs dose (D). For a bacteria in which all

cells are identical and a single event (single hit) is able to disable the cell then the graph is a

straight line which obeys the following equation:

SF ¼ekD

In a Monte Carlo simulation of 1,001 cells I was able to generate such a line in a system where it

was assumed that in each exposure to radiation a cell had a given chance of being inactivated by

the radiation. We can take a similar view to the induction of cancer, if we assume a single

mutation is able to cause carcinogenesis in an organism then we can have a similar graph of

the fraction of animals (or people) who are free of cancer as a function of the radiation dose.

However if two events are required to either kill the cell or induce cancer then the graph will be

different. A common model used for understanding radiotherapy is the LQ model which has two

constants (αand β), these constants have nothing to do with alpha and beta particles. It is yet

another unfortunate case of symbol reuse. To me symbol or term reuse is where two (or more)

areas of science/engineering use the same symbol or term for two (or more different) things. For

example activity in solvent extraction can mean either a radioactivity level (Bq kg

−1

or Bq l

−1

)ora

chemical activity. In this LQ model the SF is given by the following equation:

SF ¼eαDþβD2

ðÞ

It is possible for to have cells which can as a result of a single mutation or two mutations become

cancer cells. Such a population of cells could be dealt with using this equation with the αand β

constants. If αis zero while βis above zero then we would have a graph which would be described

by the following equation:

SF ¼eβD2

ðÞ

This would describe a system where more than one hit on a cell is required to create a cancer cell.

We need to consider the question of how long lasting is the sublethal or subcarcinogenesis

damage is. If we were to divide a dose (D) into nequal fractions each containing dose (d) then

assuming that we allow sufficient time for complete repair of the sublethal damage then accord-

ing to Zachrisson et al. the following equation would hold true (Mu, Löfroth, Karlsson, & Zackrisson,

2003):

SF ¼enαdþnβd2

½

But if we do not leave sufficient time for the sublethal damage to be repaired then according to

Zachrisson et al., we need to insert a new term into the equation to correct for this.

SF ¼enαdþnGβd2

½

One great problem is what value should Ghave, from experimental work in the 1960s Elkind et al.

exposed mammalian cells to radiation with and without a rest between parts of the dose (Elkind,

Suttongi, Moses, Alescio, & Swain, 1965), it can be argued that the value of Gcan decrease with

increasing time, then decrease again and then increase again. Coggle explains this by stating that

the first part of the dose will kill off the cells which are in the most radiation sensitive stages of the

cell cycle which will partly synchronize the cells. Also he stated that the radiation will inhibit the

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 10 of 100

progression of the cell through the cell cycle for a few hours. The initial decrease of Gwith time is

due to the repair of the cells. Next as the cells restart their cell cycle and move into a more

radiosensitive part of the cycle the value of Grises. As cells progress into a less radiosensitive part

of their cycle Gdecreases again and then it then stays low as the cells desynchronize and start to

divide again.

If we ignore the Elkind recovery effect and assume that the sublethal damage is repaired at a

rate proportional the amount of sublethal damage then we can use the ideas proposed by Lea and

Catheside (1942) which they used to explain the change in ease with which they could induce

mutations when the dose rate changed. In the following equation T

is the time required to deliver

a dose, while tand xare given by further equations (Mu et al., 2003):

G¼2τ

Tδ

1τ1xðÞ

Tδ



x¼eTδ=τðÞ

τ¼T1=2

ln 2ðÞ

Now we use the following equation to work out the SF:

SF ¼eαDþβGD2

ðÞ

While these equations about self-repair and the LQ model might seem rather dry and far from real

life, I hold the view that they are very important as they explain some things. For example in the

accident in Goiânia (1987 Brazil) a man and his wife were both exposed to radiation from a large

137

Cs source which was stolen and brought into their home. The man (Devair Ferreira) had a dose

of 7.0 Gy while his wife (Gabriela Maria Ferreira) had a dose of 5.7 Gy. His wife died while he lived

for about 6 years after his exposure, before dying of cirrhosis of the liver (He was a heavy drinker).

If we assume for the sake of argument that α= 0.16 Gy

−1

,β= 0.016 Gy

−2

= 0.4 h then we can

consider the effects of dose fractionation. If we choose a dose of 15 Gy delivered under different

conditions then we should be able to see a difference in the effect. For a single dose delivered at a

rate of 1,000 Gy h

−1

we can see that it eliminates almost all the cells, while at 0.01 Gy h

−1

a much

larger fraction of the cells survive.

From our knowledge of cancer radiotherapy we know that cells divide and the cell division can

offset the cell killing effect of the radiation. To deal with this we can use the equation where γis a

growth constant for the division of the cells.

SF ¼eαDþβGD2γTδ

ðÞ

If we set the doubling time (T

) at 3 days, then γwill be equal to 0.009627 h

−1

. We can see at low

dose rates that cell division offers another means of self-repair. Howard Thames worked out an

equation for Gfor a system which is subject to short intense pulses of radiation (no self-repair

during the irradiation) where the radiation is broken up into nʹequal fractions delivered δ

apart

then the following holds true (Mu et al., 2003):

G¼2

ðÞ

1θ



n01θðÞ

1θðÞ

þ1

θ¼eδT

½

If we now consider a 7 Gy dose delivered in four equal fractions of 1.75 Gy we can see what the

effect of altering the delay between the dose fractions will be. What we can see is that as the time

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 11 of 100

between the doses increases the ability of the radiation to kill the cells decreases. We can next

consider the effectiveness of radioactivity in the form of a sealed source implanted into a person.

Dale (1985) in an exceptional paper provided a series of equations which provide the relative

effectiveness of radiation to kill cancer cells.

For a single dose:

RE ¼1þDβ



While we normally write:

SF ¼eαDþβD2

ðÞ

The following expression for the SF is also true:

SF ¼eαD1þDβ

ðÞ½

While for an implanted radioactive seed which is allowed to decay away totally while inside a

tumour the following equation is suggested by Dale in the list of useful equations towards the end

of the paper:

RE ¼1þd0

τλ



Thus we can now write:

SF ¼eαD1þd0=τλβ=αðÞ½

As d

=Dλwe can now write the following equations:

SF ¼eαD1þDλ=τλβ=αðÞ½

SF ¼eαd0=λðÞ1þd0=τλβ=αðÞ½

The equations are not perfect when the radioactive decay constant is similar or larger than

the self-repair constant the equations for the implanted radioactive “seed”predict a survival

fraction which is unreasonable. This is likely to be due to the (λ–λ)term.Usingadoseof5Gy,

α=0.16Gy

−1

,β= 0.016 Gy

−2

and t= 0.577 h

−1

I was able to obtain this rather nonsensical

graph which suggests that the use of a very short lived radioisotope (very high dose rates) will

greatly increase the number of cells present, even without the need for cell division (Figure 4).

0,01 0,1 1 10 100 1000 10000 100000

Survival fraction

Half life

(

hours

)

Figure 4. A graph of the surviv-

ing fraction against half-life for

the simplified equation.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 12 of 100

A better equation is the full equation for the decaying source given by Dale:

SF ¼eαD1þ2Dλ2=τλβ=αðÞ

ðÞ

1=2λ1=τþλ

½

SF ¼eαd0=λ

ðÞ

1þ2d0λ=τλβ=α

ðÞðÞ

1=2λ1=τþλfg

½

With these equations we do not get a nasty kink in the line of the graph. Alternative methods of

calculation exist we could use a Monte-Carlo method based on the idea that we have cells in

three groups, unharmed, damaged and dead. I suspect that such a method would be more able

to make good predictions when the values of τand λare similar. Another method would be to

use a similar method to address the problem where the flow of cells between the three

compartments as to the method used to model americium in humans. This problem in some

ways is similar to the problem of calculating the fission product mixture very shortly after a

nuclear detonation, in his masters thesis Captain Logan Harr of the USAF compared the different

methods of calculating complex radioactive decay chains (Harr, 2007). He pointed out that the

Bateman equations are an easy way to calculate the decay of radioisotopes, but it is sometimes

impossible to use the Bateman equations. I see here a problem that the equations for cell

survival fractions with a decaying source may not be perfect solutions, they may well be

simplifications of more complex equations (which are general solutions) which work well under

the conditions which can be found in radiotherapy. While I hold the view that the following

method is not elegant and requires a lot of computer processing power it does offer a good

solution. I can summarize it with a BASIC program which should run on an Amstrad 6128

(Locomotive BASIC).

10 DIM celllive(4000); DIM cellhurt(4000); DIM celldead(4000); SF(4000)

20 Let celllive(0) =1e6; Let alpha=0.158; Let bcon=0.296; Let dosestep=0.005

30 For x=1 to 4000

40 cellhurt(x)=cellhurt(x-1)+(dosestep*bcon*celllive(x-1)-(dosestep*bcon*cellhurt(x-1)

50 celldead(x)=celldead(x-1)+(dosestep*bcon*cellhurt(x))+(dosestep*alpha*celllive(x-1))

60 celllive(x)=celllive(0)-(cellhurt(x)+celldead(x))

70 SF(x)=1-(celldead(x)/celllive(0))

80 Next

Using the same computer the program required for the SF at a given dose using a more mathe-

matically elegant solution would be.

10 Let alpha=0.16

20 Let Beta=0.016

30 DIM SF(2000)

30 For d=0–2000

40 dose=d/100

40 SF(d)=exp(−1*((alpha*dose)+(beta*dose*dose))

50 Next

One problem is that it is impossible to know if the ability of radiation to cause sublethal damage to

a cell is the same as the ability of radiation to kill a sublethally damaged cell. If we assume that

the two are equal we can use the BASIC program shown above. The values for the two constants in

the first of the two programs have been chosen to give the same final result as would be obtained

with α= 0.16 Gy

−1

and β= 0.016 Gy

−2

Returning to the problem of the implanted seed (or radioactivity dispersed in a person) decaying

away, we can see that the answers obtained by the simple Dale equation, the full Dale equation and

the iterative method are different. With very short half-lives the full Dale and the iterative method

give answers which are closer than those predicted by the simple Dale equation. It is clear that when

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 13 of 100

a dose of 5 Gy is given to the cells that the irradiation caused by the shorter lived radionuclides is

more able to kill the cells than the more prolonged irradiation at a lower dose rate.

In the case of a radioactive source implanted in a person for a time and then removed the

equation for the survival fraction given by Dale is more complex. Dale offers the following expres-

sion where Tis the time that the source is present inside the person:

RE ¼1þ2d0λ=τλðÞβ=αðÞ½

1eλT

½

1e2λT



2λ

1eTτþλðÞ



τþλ

!"#

Which then allows us to write:

SF ¼eαD1þ2d0λ=τλ

ðÞ

β=αðÞ

½

1eλT

½

1e2λT

2λ



1eTτþλðÞ

τþλ

hino

As D=d

/λ, we can now write:

D¼d01eλT



So we can now write:

SF ¼eα

d01eλT

ðÞ

1þ2d0λ=τλ

ðÞ

β=αðÞ

½

1eλT

½

1e2λT

2λ



1eTτþλðÞ

τþλ

hino

The maths becomes much more complex if we attempt to include repopulation (cell division as a

means of self-repair), this has been done by King, DiPetrillo, and Wazer (2000). but I will not be

showing these equations here. While humans are larger than cells it is important to keep in mind

that we are a collection of different types of cells which perform different tasks. Many different

types of cells are required to support life, it is possible to consider the acute effects of whole body

irradiation by considering the most radiosensitive cells which perform vital actions. The reader

might be excused for asking the question of “why is the survival of cancer cells being considered

rather than normal cells”, there are reasons why I have chosen to consider the results generated

by radiotherapy workers.

(1) They have done a vast number of experiments on the survival rates of cells using radiation

under different conditions.

(2) They have managed to obtain a good mathematical model.

(3) Evidence exists that healthy tissues obey the LQ model (Stewart et al., 2012).

What we can conclude from both the science of radiotherapy and experience from non-medical

radiation exposures (such as accidents) is that the higher the dose rate the greater the ability of

radiation is to cause acute effects such as radiation burns, damage to the digestive system and

damage to the blood cell forming tissues. While it can be argued that the loss of life, limb or

function due to radiation exposure is simply the loss of life, limb or function an alternative

argument is that the loss which occurs shortly after exposure is more serious than one which

occurs later in life as a result of the induction of cancer by the radiation. The reason for this second

argument is that the person loses more years of either life or years of having a good quality of life.

It is of the greatest importance that a situation in which members of the public suffer acute effects

is never allowed to exist. Neither during the Fukushima or Chernobyl accidents were any members

of the public exposed to a sufficient dose to cause acute effects.

One problem is that newspapers and other popular media are driven by a desire to be the first to

publish news, while the academic and scientific world is driven more by the desire to publish results

(news) which has been passed through a quality control process. As a result some rather lurid and

implausible results have appeared in the media. For example in Koriyama (Koryama) in Japan on 16

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 14 of 100

March 2011, the dose rate was 240 microGy per day (10 μGy h

−1

), the Guardian newspaper printed an

article claiming that this caused a 12-year-old girl to have nosebleeds (McCurry, 2017). I have to

admit that this is a higher than normal dose rate which would provoke some investigation from me if

I was to encounter it in a place where the normal dose rate was 0.5 μGy h

−1

. But even a whole year of

exposure to this level of radiation (88 mGy) of gamma is too small a dose to cause the changes to the

blood which would decrease the clotting of blood. Even if the dose was delivered in seconds or

minutes. However in the Guardian newspaper of the UK it was claimed that this radiation caused a

child to suffer nosebleeds. While it would be unreasonable for me to claim that newspapers are

never right, I would like to take this chance to warn the reader to be careful of newspapers and other

non-peer reviewed sources. But I do need to warn that sometimes the peer review system does not

work. While Winston Churchill has been reported to have said:

“that democracy is the worst form of Government except for all those other forms that have

been tried from time to time”

I would say that peer review is a bad system for quality control but it is the least bad system so far.

It has failed from time to time in different ways. For example Mangano and Sherman (2012)

published a paper which claimed that Fukushima fallout caused infant deaths in the western part

of the USA. A key part of the paper was the claim that the rate of death had increased after the

Fukushima event. I have to admit that there was a small increase of the infant death rate, but an

examination of the data does not indicate that the increase was due to the Fukushima event

(Moyer, 2011). The raw data can still be obtained from the Center for Disease Control (CDC) in the

USA (Anon, 2011). The paper of Mangano and Sherman contained a series of problems. For

example it was pointed out by Gale that the deaths claimed by Mangano and Sherman were

occurring after trivial exposures, while larger exposures (medical diagnostic X-ray examinations

and diagnostic nuclear medicine) do not cause deaths due to acute radiation effects (Gale, 2012).

Gale also pointed out that in Japan no reactor site workers had died despite being exposed to far

greater doses than the American general public. It has been pointed out that the changes in death

rate reported by Mangano and Sherman were not statistically significant (Körblein, 2012). While it

was pointed out by another person that no mechanism is known that explains how such small

doses might cause death and no sensible dose/response relationship can be seen (unexposed

populations in the USA had the highest death rate increases after Fukushima) (Wolf, 2012). I also

note that the paper by Mangano and Sherman rather than considering the degree of exposure

often simply considered the fraction of air, precipitation (rain. etc.), milk and drinking water in

which radionuclides could be detected. I would like the reader to consider the fact that in all fruit,

vegetables, fish and meat that it will be possible to detect

C and

K. This does not indicate that

all fruit, vegetables, fish and meat contains dangerous amounts of radioactivity. I hold the view

that the peer review and editorial processes failed to prevent the publication of a paper which has

multiple deep flaws which are easily apparent.

Doses of radiation too low to induce the acute effects, or exposures which are too protracted to

cause acute effects can cause harm byinducing cancer. It is important tonote that an acute exposure

can induce cancer, but here we will consider the only late effects such as cancer. In Japan when the

atomic bombs were dropped the population on the ground nearby received various doses, this dose

was delivered over a very short time. In some of the data the relationship between the cancer

incidence and the dose appears to obey a LQ or quadratic model. If we assume for a moment that

the LNT model applies than for both atomic bomb survivors and radiation workers who receive large

doses then we need to correct the LNT model. Instead of being able to write:

EAR ¼μD

We need to correct the LNT model to take account of the cell killing effect of the radiation. If the

radiation is delivered in a short pulse as an atomic bombing, a single pulse criticality accident or

being present in the shielded cell of an irradiator or radiographic enclosure for minutes or seconds

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 15 of 100

while the source is exposed then we can use the following equation where μis a constant for the

induction of cancer by radiation.

EAR ¼μDe

αDþβD2

ðÞ

If the dose is fractionated into smaller doses or delivered over a long time then we need to

consider the replacement (repopulation) and self-repair of the cells. This dose fractionation

represents an exposure more similar to the commonly used fractionated radiation therapy for

cancer or an occupational exposure in the early days of radiation work. I sincerely hope that

radiation workers are not being currently exposed to doses which kill a significant fraction of their

cells. If we assume that the likelihood of developing cancer is proportional to the number of

mutated cancerous and precancerous cells which are generated by radiation. Then for a fractio-

nated dose of radiation where the cells are allowed to repair all their sublethal damage between

doses we have to consider the ability of cells in the tissue to repair themselves and/or the ability of

the tissue to replace dead cells by cell division. This ability in the equations is taken care of by a

constant x, I strongly suspect that if the conditions of the irradiation were to be changed than x

will also change. To my mind while xis a useful constant it is a fudge factor.

The loss of the original cells is given by the equation:

NDðÞ¼N0eα0D

αʹis given by the following equation where d

is the dose per fraction:

α0¼αþdfβ

The appearance of new cells (repaired or replacement cells) is given by the following equation:

RDðÞ¼ No

þα0

α0

þeDα0

α0

α0þα0eD





While the number of mutated cells which have the potential to develop into a carcinoma is given by:

MCDðÞ¼ μN0eα0D

α0þ

α0

þeα0D

α0





α0þα0eD





While the number of mutated cells which have the potential to develop into a sarcoma is given by:

MSDðÞ¼ μN0eα0D

α0þ

α0

þeα0D

α0





α0þα0eD

þα0DþD



When the dose is small the equation for carcinoma induction will give an answer which is

similar to that given by the LNT model. Another version of the equation for the induction of

carcinomas exists. For a tissue which is unable to repair itself or for cells to repopulate R=0

while for a tissue which can fully repair (or repopulate) itself R= 1 (Schneider, Stipper, &

Besserer, 2010).

EAR ¼μeα0D

α0R12RþR2eα0D1RðÞ

2eα0RD=1R

This model can be fitted to the statistics for the induction of breast (Schneider et al., 2011) and

lung (Schneider et al., 2010) cancers during radiotherapy. The value of Rin this equation can be

found using the following expression:

R¼

þα0

These equations which consider the effects of cell death and repopulation which are used to model

carcinomas have at their core the assumption that the likelihood of carcinogenesis is proportional

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 16 of 100

to the dose at small doses. In the case of radiation delivered over a very short time the carcino-

genesis (Japanese atomic bombings) seemed to obey the LQ model. There is a problem that the

population which was exposed to high doses and survived the heat, blast and acute radiation

effects was relatively small. As a result the statistical error on the number of cancers will be large.

If Poisson statistics are assumed for the appearance of cancer cases then simply by virtue of the

small number of people who received large doses and then lived sufficiently long to have the

opportunity to develop the uncertainty on the cancer risks of the larger exposures are large.

While the atomic bomb exposures occurred over a similar time to some short duration expo-

sures which some radiation workers might experience during some types of accidents (such as

those which can occur in the shielded cell of an irradiator or radiographic enclosure) in many

accidents it is likely that both workers and members of the general public will be exposed to

protracted exposures lasting hours, days, weeks or even longer. A meta-study of the induction of

cancer by radiation in animals suggests that for protracted exposures the dose response is not LQ

(Haley, Paunesku, Grdina, & Woloschak, 2015). I cannot hope to be able to give a detailed review of

the relationship between radiation exposure and carcinogenesis in detail but I hope that I have

made it clear that it is difficult to decide quite how carcinogenic radiation is. The question of does

radiation cause serious harm to the circulatory system has been the subject of some papers as I

have mentioned in the first review.

It is important to consider before we explore serious accident chemistry the fact that the fear

and terror associated with radiation can cause harm. Even scientists and other people who regard

themselves as rational can be affected, I can admit that 17 years ago when I did radioactive

chemistry for the first time I experienced fear and anxiety which caused some physical symptoms

of stress to appear in me. While in my case the transient terror had no lasting effect it is quite

credible that in some cases the fear of radiation has been more deadly than the radiation. In

Japan an increase in the death rate of elderly people who were evacuated rapidly from care homes

was observed after Fukushima (Nomura et al., 2016). As the increase in death rate in the popula-

tion who were evacuated later in a calmer more ordered manner was much smaller, we can

conclude that those who were evacuated later were less likely to die.

The radiation exposure, due to the Fukushima accident, of the nursing home residents was lower

(0.01 mSv) while those evacuated later received a higher average dose (0.4 mSv). If we assume

that a dose of less than 1 Gy is only able to cause death by randomly inducing cancer and that the

risk of developing cancer in a given year is increased throughout a person’s life. Then we would

expect that the younger a person is that the greater their loss of life expectancy as a result of the

radiation exposure. In the paper about the nursing home the older a person the greater the life

shorting effect of the incident was. If the deaths were caused by radiation exposure then we would

expect that the more exposed persons would be either more likely to suffer an adverse outcome.

But in this case the persons exposed to less radiation lost more life expectancy than those exposed

to the higher (but trivial dose) (Table 1).

The same authors considered the life shorting effects of 25 and 100 mSv doses of radiation, they

calculated that these doses would cause a 80-year-old man to lose 0.2 and 1.1 days of his life. It is

interesting that Greenpeace in their document entitled “Unequal Impact”(Ulrich, 2017) and the

World Information service on Energy (Anonymous, 2011) (Olson, 2011) have stated that radiation

Table 1. The number of days lost from the life expectancy of a person requiring low to medium

care evacuated from a care home in the Fukushima area.

Person Rapid evacuation Later evacuation

Man (80–89) 80 6.3

Woman (80–89) 53 3.9

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 17 of 100

is more harmful to women than it is to men. The paper by Murakami et al. does consider female

residents, for a women aged 80 using the standard methods they predict that a dose of 25 mSv

will cause the lady to lose 0.26 days of her life and the 100 mSv dose will cause her to lose 1.4 days

of her life. While these values are higher than the loss of life expectancy for the 80-year-old man,

the difference is small.

As the uncertainties on estimates of how carcinogenic radiation is to humans are large, I want

to make a few things clear.

(1) Ionizing radiation is carcinogenic, it is an inescapable fact that exposure to radiation doses

above 1 Gy are clearly carcinogenic.

(2) At low doses the statistical errors on the data are very large. It is not totally clear if the

response for some cancers is linear or if there is some threshold or threshold like behaviour.

(3) The younger a person is at the time of exposure the more harmful (carcinogenic) a large

dose of radiation is. This is biologically plausible, children have longer life expectancies than

adults (more time for radiation induced cancers to develop) and they have higher rates of

growth (and cell division) than adults.

(4) Ignoring the special case of children, anyone who claims that one group of humans are

more/less sensitive than another to radiation should be viewed with a healthy degree of

scepticism. My advice is ask them what evidence they base their judgement on and ask how

statistically significant the difference is.

(5) Anyone who disagrees with the ICRP on the question of how dangerous radiation is should

be treated with a healthy degree of scepticism. While sadly the ICRP are not incapable of

making an error, their position was arrived at after considering a lot of data. While this data

may not be perfect it is likely to be some of the best data in the world. My advice if you

encounter someone who states that the ICRP is wrong is to politely ask for the evidence

(including statistical evidence).

Finally before we go on to consider some of the chemical (and occasionally physical) processes

which govern nuclear reactor accidents and some of the other accidents in the nuclear fuel cycle.

We should reflect on the question of what is an acceptable exposure. If we look at UK law we will

notice that over the years the dose limits for workers has decreased they have decreased. In the

time between 1961 and 1984 the legal classified worker whole body limit for gamma rays and

other penetrating radiations was 120 mSv per year. From 1985 to 1999 the yearly whole body limit

classified worker limit was 50 mSv while since 1999 it has been 20 mSv per year. This to me

suggests that while the medical management of radiation induced diseases might be improving

that both science and society in general has become stricter with regard to the question of “what

is an acceptable occupational radiation exposure.”

2.2. Types of nuclear reactor accidents

Before we start to discuss the different types of accident we need to consider the scale by which

reactor accidents are measured, this is the International Nuclear Event Scale (INES) (Abe et al.,

2013). This was devised by the IAEA and the OCED after Chernobyl as a means of classifying, rating

and communicating the severity of nuclear accidents. The scale has eight levels (0–7). At the

bottom is a level 0 event which has no impact on health, safety or the environment. The top level is

level 7. The order of events are anomaly (1), incident (2), serious incident (3), accident with local

consequences (4), accident with wider consequences (5), serious accident (6) and major accident

(7). Non-radioactive events such as workers falling off the roof of a nuclear plant, being shocked

with electricity in the switch yard and even stubbing their toes in either the control room or the

containment are not considered on this scale. Unless one of these “non-nuclear”and “non-radio-

active”accidents has an effect on the safety of a nuclear or radioactive site. For example a

careless HGV driver who rams a pylon causing it to crash to earth into the switch yard thus

disabling the electrical power systems of a site could be accessed on the INES scale, but if this

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 18 of 100

dire driver was to ram the restaurant killing the catering staff it would not be considered. The scale

considers the impact of an event on three different things:

●People and the environment,

●Radiological barriers and controls, and

●Defence in depth.

The impact on people and the environment considers the effect on the general public, a release of

radioactivity into the atmosphere can be used to rank an event. The scale is based on

131

I, a series

of other radioisotopes are given conversion factors to allow them to be compared with

131

I. For

example

241

Am has a value which is 8,000 times that of

131

P has a value of 0.2 times that of

131

I while noble gases have a value of zero. For example a release of 1 TBq of

241

Am is ranked as

being the same as a release of 80 PBq (8,000 TBq) of

131

I. While a release of 1 TBq of

Pis

regarded as being the same as a release of 200 GBq of

131

Based on radiation doses to humans the event can also be assessed for example if an event

causes a non-lethal radiation injury then it must be rated at least three, a fatal radiation injury will

result in a rating of at least four. Even if no human is harmed (or even mildly irradiated) by an

accident and no radioactivity is dispersed into the environment an event can still receive a score.

For example the Three Mile Island accident was thought by the IAEA to have only exposed the

public to a dose not greater than 0.8 mSv. If the accident was judged on dose to the public alone it

would have a very low score (maybe 0). But as part of the core was molten (more than a few

percent) it was rated at level 5. Some examples of real life events which have been rated in the

INES scale are included in Table 2.

I judged the Casablanca lost

192

Ir source which occurred in 1984 to be a level 5 event as it killed eight

members of the public. For between 1 and 3 deaths the minimum rating is 4, but when more than a

few deaths occurs then the rating is increased by one level. It is not considered likely that a radiation

source accident would killmore than 30 people, but if it did so then the event would be rated at least at

6. For comparison I have added four fatal railway accidents, while they should not be rated on the INES

Table 2. Examples of different accidents rated on the INES scale.

Score Name or location of event Short description

3 Lima (Peru 2012) Over exposure of radiographer (1.9 Gy), loss of finger.

3 Vandellos (Spain 1989) Fire causes near accident at nuclear power plant

4 Fleurus (Belgium 2006) Non-fatal overexposure of worker at an irradiator

4 Tokaimura criticality accident Improper handling of enriched uranium (2 deaths)

4Wrawby Junction rail crash (1983) Crash between freight and passenger trains (1 death)

5 Goiânia accident

137

Cs source broken up in scrap yard, 4 deaths

5 Casablanca (Morocco, 1984) Lost

192

Ir source kills eight members of the public

5 Windscale fire Fire in air cooled graphite reactor

5 Three Mile Island Unit 2 Nuclear power plant accident (LOCA)

5Glanrhyd Bridge (1987) Train carriage in Wales falls into a river (4 deaths)

6 Kyshtym accident Explosion in waste tank

6Moorgate tube crash (1975) Northern line train crashes into wall (43 deaths)

7 Chernobyl accident Serious nuclear power plant accident (RIA)

7 Fukushima accident Serious nuclear power plant accident (LOCA)

7Ufa train disaster (USSR, 1989) Two trains blown up in an accidental gas explosion

A sensible behaviour before doing anything with radiation or irradiation equipment is to consider “what will happen

if I do X before you do X rather than doing X without thinking about it and suddenly finding out what happens.”

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 19 of 100

scale based on the loss of lives I have ranked them as if they were radiation source accidents with no

dispersion of radioactivity. While the IAEA do not consider a radiological accident involving a radio-

active source that kills more than 30 people to be credible, I hold the view that a fatal accident which

kills over 500 people then the spirt of the logarithmic INES scale would indicate that it would be rated

at4+3=7.Iwillnotbediscussingindetailthefatalandnon-fatalfoodandmedicalproduct

irradiators, these accidents have been associated with a number of fatal injuries to workers. All the

irradiator accidents which I am aware of occur in the following way.

(1) Something goes wrong inside the irradiation chamber, thus attracting the interest of an

operator.

(2) The operator then enters the room, sometimes they ignore alarms and defeat safety devices.

(3) The operator then receives a dose of radiation.

(4) The operator is then either dies in hospital or has some other serious life altering injury.

If the reader wishes to it is possible to have some further understanding and experience of

accessing events then on-line teaching tool provided by the IAEA exists (IAEA, 2014).

I have chosen to write this review about fission reactors, this is because with the exception of

stars it has been impossible to obtain a self-supporting sustained fission reaction in a system

which emits more energy than that it consumes. The lack of fusion power plants has not totally

prevented the idea of an accident in a fusion plant being considered. If an accident was to occur in

a fusion plant such as ITER it could reach level 6 on the INES scale (Nie, Ni, & Wei, 2017). It is

important to note that the radionuclides which would be important in such an accident are

different to those which are important in a fission plant. For a start we will have little or no

radioiodine. But in terms of safety the fusion reactors have a weak point, this is the vast tritium

inventory. While the fuel in the vast majority of fission power reactors is a high melting point solid

the fuel in a fusion reactor is either in the form of gas or plasma. As a result the tritium in a fusion

reactor has the potential to become very mobile. It is likely that in a fusion plant much of the

tritium will be stored in the form of a stable metal hydride such as uranium hydride.

In a fusion reactor accident activated metal may be liberated in the accident. Neutron activation

of the water cooling loops will be able to generate some

Cr,

Mn,

Fe,

Co,

Co and

Ni. While the plasma facing tungsten will contain

Co,

179

Ta,

182

Ta,

182m

Ta,

183

Ta,

184

Ta,

186

Ta,

179

179m

181

185

185m

187

184

Re,

186

Re,

188

Re and

188m

Re (Taylor & Raskob, 2007). During

the normal life of a plant and during an accident dust can be formed by the erosion of metal

surfaces, if this dust is mobilized during an accident this could contribute to either workers or

members of the public being exposed to radiation. If the plant uses a lithium/beryllium fluoride

blanket as a tritium breeding system then within this some

F could be generated by the n.2n

reaction. This

F could add to the dose due to an accident. Due to the difficulty of causing a fusion

reaction to occur, I do not consider an accident due to a surge in fusion rate to be reasonable. I think

that the main types of accident will be a loss of cooling accident and a loss of vacuum accident

(LOVA). These two types of accident have been considered (Malizia, Poggi, Ciparisse, Rossi, Bellecci

and Gaudio, 2016). It is interesting to note that in some facilities that air can become radioactive as a

result of exposure to very high energy radiations, for example

CasCO

NasN

and NO and

as O

and NO has been found in the air at a 100 MeV LINAC (LINear ACcelerator) (Endo, Kikuchi,

Izawa, & Ikezawa, 1995). These proton rich nuclides are likely to be formed by photonuclear

reactions due to very high energy gamma rays. While high energy neutrons are able to create

and

Cl from

Ar and

Br and

Br from

Kr. These radiohalogens can become attached to existing

aerosol particles (Endo et al., 2003). I imagine that nothing would prevent other radionuclides

absorbing onto existing aerosols.

While in the high energy proton facility in Japan

Be was observed, this radionuclide is unlikely to

be formed in a nuclear reactor system. According to some Japanese workers in the proton

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 20 of 100

accelerator sites primary and secondary particles with 30 MeV or more energy are able to form this

beryllium radionuclide by spallation of nucleons from the nitrogen and oxygen in the air (Kondo,

Muramatsu, Kanda, & Takahara, 1984). However some Russian workers claim that protons with

little more than 10 MeV can form

Be from

N (Larin, Malyshevskii, & Fomin, 2014). Even 10 MeV

protons are particles which are very high in energy compared with the typical fission neutron from

235

U (2 MeV). Before we leave

Be there are two interesting things about it.

Firstly the

Be is thought by Kondo et al. to form either beryllium oxide or the hydroxide which

then attaches to non-radioactive aerosol particles to form the radioactive aerosols. Secondly it is a

radionuclide with rather interesting decay kinetics. The rate of decay is a function of the chemical

environment of the nuclide. Some of the young earth creationists (Walker, 2000) have pointed out

that the decay of

Be is very dependent on the chemical environment of the beryllium (Huh, 1999).

This might be a shock, but it is true (Mazzocchi, Janas, Bączyk, Fynbo, & Köster, 2012). The half-life

Be is influenced by the chemical environment of the radionuclide. It is reasonable to state that

Be is a special case. Firstly

Be decays by electron capture with a very low decay energy (862 keV).

As the decay energy is shared between an emitted positron and the neutrino it is unlikely that the

nuclide will be able to form an antielectron (positron) and eject it from the nucleus.

One consequence of this is that as the decay energy is low compared with the energy required to

form a positron the

Be is unable to decay by β

and must undergo an electron capture reaction.

Secondly as a neutral atom of beryllium has four valance electrons and can reach an oxidation

state of +2, it is possible to significantly alter the electron density near the atomic nucleus. As a

result different chemical forms of

Be decay at different rates.

While

Be in precipitation from the atmosphere (natural fallout) is important as a measure of solar

activity, the decay of

K into

Ar is important as a radioactive reaction using for dating rocks. The

reader may be interested to know that experiments have been performed in which the rate of the

decay of

K has been measured for different chemical forms, no difference was observed (Norman

et al., 2001). As in the case of potassium, any change in the chemical environment of the potassium

atom will have a far smaller effect on the electron density close to the nucleus. This is because the

uncharged potassium has 21 electrons while beryllium only has four electrons per atom.

But back to reactor accidents. The first major reactor accident in the west was the Windscale

reactor fire (1957), this was a fire in an air cooled graphite moderated isotope and plutonium

production reactor in the north of England. The reactors were rated for 180 MW of thermal output,

the fuel load was 180 tons of uranium (72,000 cartridges) and the moderator was 1,900 tons of

graphite. The reactors are 15 m diameter graphite cylinders which are 8-m long. The reactor was

designed for a maximum uranium temperature of 395°C (Sheil, Botzem, & Johnston, 1999).

The fire dispersed radioactive iodine, cesium and some other radionuclides including

210

Po over much

of Europe (Stewart, Crooks, & Fi sher, 1961). The polonium was released from bismuth containing capsules

which were being neutron irradiated to form polonium. The polonium was wanted as an alpha emitter for

use in nuclear weapons. As much of the non-noble gas release from the reactor accident was radioactive

iodine, in response to the accident a considerable amount of work was done on iodine.

Energy will accumulate in the graphite of a nuclear reactor which operates at a low tempera-

ture, if this energy was allowed to accumulate without a release then it could lead to a sudden

energy release (Bell et al., 1962). Often when neutron irradiated graphite is heated a release of

energy is observed at 200°C, a smaller amount of energy is released at higher temperatures.

However when graphite is either irradiated to very high neutron doses or is irradiated at higher

temperatures then the release of energy at 200°C becomes smaller when compared with the

releases at higher temperatures (Mitchell & Taylor, 1965). It is normally considered that the

annealing reactions are first order reactions whose rate can be described by the Arrhenius

equation:

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 21 of 100

dt¼υN0eEA=kTðÞ

On heating the number of the defects will decrease. In one study the effect of the rate of heating

(1–100°C min

−1

) was considered at length (Iwata, 1985), what Iwata observed was evidence that

several different interstitial clusters of different size exist in neutron irradiated graphite. In one

recent study of graphite subject to fast neutron bombardment (5.67 × 10

to 1.13 × 10

−2

7.88 × 10

−2

−1

and below 100°C) using differential scanning calorimetry energy releases at

150, 200, 230 and 280°C were observed, these peaks correspond to activation energies of 1.31,

1.47, 1.57 and 1.72 eV respectively (Lexa & Dauke, 2009).

With higher neutron doses it was found that the temperature at which the energy is released is

shifted to a higher temperature even when the graphite was irradiated below 100°C (Lexa & Kropf,

2006). Other workers have also observed energy releases over the range 200–600°C (Lasithiotakis,

Marsden, & Marrow, 2013) and it is known that the graphite interlayer spacing changes after neutron

irradiation. Lexa and Kropf along with other workers have observed that the caxis of the graphite unit

cell increases in length as the Wignerenergy level increases. But itis important to keep in mind that the

higher the irradiation temperature the less energy will be retained as Wigner energy by the graphite.

Using the graphite plunger from a control rod taken from unit 2 of the Kursk nuclear power plant

(RBMK reactor) indicated that after 6.5 years of service some of the properties of this graphite had

changed. For example the thermal conductivity of the graphite had decreased as a result of

neutron bombardment and instead of the thermal conductivity of graphite decreasing as the

temperature rises the thermal conductivity of the neutron bombarded graphite increased as the

temperature rises (Platonov et al., 2003).

The Wigner energy is deposited in graphite by bombardment by fast neutrons. It is important to

note that the action of the neutrons on the graphite create a series of different types of defects.

Some of these defects are very easy to anneal out of the graphite. While some of them are so

stable that they require heating to a very high temperature (1,400°C) before the graphite will relax

back to normal (Telling & Heggie, 2007). Telling and Heggie in their extensive review considered the

Windscale piles, rather than returning the graphite to the virgin state they expressed the view that

during each anneal that residual defects with higher activation energies (release barriers) were

formed. This contributed to an accumulation of Wigner energy in the graphite. They suggested that

an aggregation of the defects was occurring.

It has been stated in interviews that the fuel at the Windscale piles had been modified in an

attempt to increase the neutron flux in the reactor and thus the production of plutonium and other

products. I hold the view that this could contributed to the accident. It is impossible to know

exactly what caused the Windscale fire, but it is reasonable to state that during the ninth

annealing of the graphite pile that the reactor overheated. It is likely that a tritium generation

capsule containing Mg/Li alloy burst open before igniting. My own view is that the likely root causes

of the fire were a poor reactor design combined with a misjudgement made by a senior person.

This was the choice to increase the neutron flux in the reactor (and thus the power level). In an

attempt to create a hydrogen bomb the UK government needed a large amount of tritium.

Together with plutonium and polonium the tritium was needed for nuclear bombs.

The resulting fire caused a large release of radioactivity. While the filters on top of the chimneys

would have reduced the size of the radioactive release they were not able to prevent all solid

particles from escaping. It was reported that

137

Cs,

103/106

Ru and

Zr were found on nearby farms

after the accident (Dunster, Howells, & Templeton, 2007). While it is conceivable that the ruthe-

nium could have become mobile as the tetroxide the zirconium would have had to leave the pile in

the form of a solid. The krypton would have long since decayed into one of the solid forming

nuclides in the following decay chain before it would have been able to diffuse out of the fuel.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 22 of 100

95Krðt1=

20:78 sÞ!

95Rbðt1=

20:38 sÞ!95Srðt1=

224 sÞ!95Yðt1=

210:3 minÞ!95 Zr ðt1=

264 daysÞ

The MAGNOX and AGR reactors operate with the graphite at a higher temperature than the

Windscale piles, as a result the accumulation of Wigner energy in the graphite is a smaller problem

in these reactors. While the existence of the Wigner energy problem might make the idea of a

graphite moderated reactor appear unattractive to some readers, it is important to note that the

absence of water from the core of a gas cooled reactor eliminates the possibility of a Boiling Liquid

Expanding Vapour Explosion (BLEVE) in the event of a temperature increase in the reactor or as a

result of a sudden pipe break. During the Chernobyl accident which is discussed later, the surge in

the thermal power output of the nuclear reaction caused a steam explosion. A steam explosion is a

BLEVE where the liquid is water, the steam explosion broke open the core and may have been

followed by a hydrogen/air explosion at Chernobyl.

At a similar time to the Windscale fire, in the Soviet Union an accident with a rather more

disagreeable effect occurred (INES level 6). This event was first brought to public attention in the

west by Zhores Medvedev (An exiled Soviet geneticist) in a 1976 article (Medvedev, 1976) in New

Scientist (Norman, 1983). It is not clear what was known in the west by “the establishment”,a

1982 document (Soran & Stillman, 1982) from Los Alamos argued that the accident at Kyshtym

never occurred and that “The Soviets successfully, albeit rather unsensationally, created a con-

taminated area near Kyshtym through carelessness and blatant disregard for their people or their

surroundings”. Ignoring the form of radiological hooliganism known as “dirty bombing”Iam

unsure how the creation of a contaminated area can be a success. To my mind contamination is

the presence of something which is unwanted. On the other hand it has been claimed by some

that the CIA have known about this accident for many years but for political reasons they choose

to keep their knowledge secret.

The reason I regard the Kyshtym accident as being worse than the Windscale Fire is that the

effects of the Kyshtym accident were worse due to the release of more activity which included the

long lasting

Sr. A recent Russian estimate is that 740 PBq of activity was released during the

Kyshtym accident (Akleyev, Krestinina, Degteva, & Tolstykh, 2017). This compares with Garland and

Wakefield’s estimate that 35 PBq of radioactivity was released by the Windscale fire. According to

Garland and Wakefield’s estimate the Windscale fire released 8.5 PBq of non-noble gas radio-

activity, which is a little more than 1% of the Kyshtym release. Much of the radioactivity released

by the Windscale fire was radionuclides with short half-lives (

133

Xe t

= 5.2 days,

131

= 8 days

and

132

Te t

= 3.2 days), while much of the Kyshtym accident release was longer lived radio-

nuclides such as

Zr (t

= 64 days) and

144

Ce (t

= 285 days). All the radionuclides which were

listed as major components of the release have such shorter lived daughters except for

Zr. As a

result for those other than

Nb I have chosen to consider their radioactivity as an extension of the

parent’s radioactivity.

The release was caused by a violent event inside a waste store, at Mayak PA a high level

radioactive waste (a mixture of acetate and other salts) (Jones, 2008) was stored in metal tanks

which were inside concrete vaults. Each full tank contained between 70 and 80 tons of waste. The

tank was a cylinder with a plain bottom (diameter 8 m and height 6 m) which was made of

stainless steel. This was within a reinforced concrete canyon (diameter 9 m and height 7.4 m). The

canyon had a circular lid (circa 0.8 m) made of concrete and was then covered with between 1 and

1.5 m of soil (Avramenko et al., 2000). The mixture of radioactivity, water, sodium nitrate, sodium

acetate and some potassium dichromate was heated by the decay heat until it boiled dry. The

solid residue contained a fuel sodium acetate (22.2%, w/w) and two oxidants (sodium nitrate and

potassium dichromate sum 75.8%, w/w). If we assume all of the oxidant was sodium nitrate then

in 1 kilo of the solid residue 2.71 mol of sodium acetate were present and 8.92 mol of sodium

nitrate were present. Total combustion of sodium acetate can occur by the following reaction:

2NaC2H3O2þ4O2!4CO2þ3H2OþNa2O

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 23 of 100

If sodium nitrate was heated it can decompose to sodium nitrite according to the following

reaction:

2NaNO3!2NaNO2þO2

If sodium nitrate was subject to greater heating then it might be possible to convert it into oxygen,

nitrogen and sodium oxide as according to the following reaction:

4NaNO3!2Na2Oþ2N2þ2O2

The stoichiometric mixture for the reaction in which sodium nitrate is converted into nitrogen gas

will be a 4:1 (by moles) mixture of sodium nitrate and sodium acetate. Chillingly the mixture in the

tank was rather close to this ratio at 3.3:1.0:

8NaNO3þ2NaC2H3O2!4CO2þ5Na2Oþ3H2Oþ4N2

Modern nuclear fuel reprocessing uses the extraction of uranium and plutonium from nitric acid

by solutions of tributyl phosphate in what is known as the PUREX process. It is normal to extract

both the uranium and plutonium from the nitric acid solution of the fuel (pregnant leach liquor)

and then back extract them, before reextracting them again. The process is designed to extract

uranium(VI) and plutonium(IV) from the fuel. The plutonium oxidation state can be adjusted with

things like sodium nitrite or nitrogen oxides before the extraction. By reducing the plutonium to the

+3 oxidation state with a reducing agent such as ferrous ions, hydroxylamine or hydrazine the

plutonium is converted into a form which does not extract from nitric acid with tributyl phosphate.

Thus the uranium and plutonium can be separated. Chromate and acetate are not normally used

in the PUREX process so the contents of the waste tank suggest to me that the Soviets at the time

were not using PUREX chemistry to obtain plutonium. The method of plutonium separation is

based on the formation of acetate complexes of the actinides. The uranium (Paramonova &

Kalychev, 1966) and plutonium (Moskvin, 1969) form complexes with acetate (Table 3).

It is known that uranium and plutonium can be extracted from acetate media using tri-iso-

octylamine mixed with xylene (Moore, 1960), it could have been reasoned that in the Soviet Union

that such a process was used in the early days at Mayak. But the waste at Mayak associated with

the accident was not from a solvent extraction process. The chromate in the waste is also of note,

Moore reported that very little extraction of trivalent and tetravalent plutonium from the acetate

media into the amine containing organic layer occurred. But hexavalent plutonium (PuO

22+

) was

well extracted. It is well known that plutonium redox chemistry is very complex, it is possible for

four different oxidation states of plutonium to coexist in aqueous media. Complicating the matter

further plutonium tends to disproportionate according to the equation:

PuO22þþPu3þ!PuO2þþPu4þ

Things are further complicated by the fact that in a concentrated plutonium solution the water is

subject to a lot of alpha radiation. The radiation creates hydrogen peroxide and other species

which can alter the redox state of the plutonium. We need to consider several redox couples:

Table 3. Thermodynamic stability constants for acetate complexes of uranium and plutonium.

Metal Log

of thermodynamic stability constant

22+

2.52 4.4 ± 0.2 6.2 ± 0.2

2.85 5.06 6.57 7.68 8.42 8.74

2.88 4.90 7.60 9.90 12.5 14.8 17.2 20.3

PuO

22+

3.02 5.47 7.28 8.06

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 24 of 100

Pu4þe!Pu3þ;0:930 V 1 M HNO3at 25oCðÞ

PuO22þþePuO2þ;1:15 V 1 M HNO3at 25oCðÞ

We need to consider also a more complex reaction:

PuO2þþ4Hþþe!Pu4þþ2H2O;0:909 V 1 M HNO3at 25oCðÞ

The redox potential for this reaction will change as the proton concentration changes as the

reaction involves protons. The Nernst equation can be used to predict the emf of a cell which

does not have everything at 1 mol per litre. If we assume for a moment that all activity coefficients

are 1 then we can write:

E¼E0RT

nF ln Q



In this case Qis given by the following equation:

Q¼Pu4þ



PuO2þ



Hþ



It can be reasoned that as the hydrogen ion concentration decreases that it will be easier and

easier to oxidize plutonium(IV) to plutonium(V).The complex thing about chromium in acidic media

is that a vast number of redox reactions are possible. The book by John Emsley lists a rather large

number of redox reactions for chromium.

Cr2O72þ2eþH2O!2Hþþ2CrO43;0:55V

Cr2O72þ6eþ14Hþ!2Cr3þþ7H2O;1:38V

CrO43þeþ8Hþ!Cr4þþ4H2O;1:34V

Cr4þþe!Cr3þ;2:1V

This data suggests that it is possible for chromate to oxidize plutonium into the hexavalent state.

The Russian radiochemical literature it is pointed out that an acetate precipitation method was

preferred in the early Soviet nuclear industry (Zilberman & Romanovskii, 2003). The process formed

solid sodium uranyl triacetate Na[UO

(OAc)

] which was mixed with the plutonyl compound. It has

been reported that the sodium uranium(VI) triacetate has a cubic cell (a= 10.670 Å), while the

neptunium(VI) and plutonium(VI) compounds are isostructural and have cubic cells which are

slightly smaller (10.659 and 10.643 Å respectively) (Zachariasen & Plettinger, 1959). What hap-

pened in the process was that the irradiated fuel was dissolved in nitric acid yielding a solution in

1–2 M nitric acid. This was then treated with sodium dichromate to oxidize the plutonium to

plutonium(VI). Then the solution was adjusted to a near neutral solution of 5 M sodium nitrate, 1 M

acetic acid and 0.5 M sodium acetate. The uranium and plutonium then were allowed to pre-

cipitate. The supernatant, containing most of the fission product radioactivity, was then removed

and the solid washed with an acetate solution. The mixed plutonium/uranium solid was then

redissolved and the process repeated to reduce the radioactivity of the solid. When the fission

product radioactivity was sufficiently low the plutonium was reduced to plutonium(IV) or pluto-

nium(III). A wide range of reducing agents could have been used for this, the most obvious one to

my mind is iron(II).

The plutonium would have remained in solution while the uranium was then precipitated with

acetate to form a plutonium only solution. The plutonium was then reoxidized to plutonium(VI)

which was then converted into sodium plutonium triacetate. All this precipitation and redissolving

would have generated vast volumes of liquid waste, and under some conditions it could have

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 25 of 100

caused the metals to deposit onto surfaces in the plant and/or formed small (and mobile particles).

During the second world war in the United States of America plutonium was isolated using another

precipitation process based on bismuth phosphate. As the bismuth phosphate process is better

known than the acetate process I will not dwell on it.

One can imagine that in the same way as perchlorate is a large anion which makes many

cations such as the iron-tris(2,2ʹ-bipyridyl) dication form water insoluble crystalline solids the

uranyl triacetate anion is a large anion which has the potential to form insoluble salts with cations.

But cesium and rubidium do not form solids with uranyl zinc acetate with the same ease (Barber &

Kolthoff, 1929), thus there must be something special about sodium. A search of the crystal-

lographic literature indicates that a vast array of uranyl triacetate complexes exist.

For cesium two cesium uranyl triacetates appear in the Cambridge database, there is a cubic

(Serezhkina, Vologzhanina, Klepov, & Serezhkin, 2011) and an orthorhombic (Serezhkina,

Vologzhanina, Klepov, & Serezhkin, 2010) solid. The cubic compound has 16 uranium atoms in

the unit cell, the unit cell contains 12 locations which are either cesium or barium. This ratio

suggests to me that some of the “cesium”locations in the solid may in fact be barium atoms. The

solid is a disordered solid with sites being randomly occupied by either cesium or barium. A given

site has a 0.333 probability of being occupied by a barium and a 0.666 probability of being

occupied by a cesium. The orthorhombic cesium compound has uranyl triacetate groups being

bridged by the cesium cations (Figure 5).

The cesium atoms in the orthorhombic solid have a coordination number of 7, six of the oxygens

in the inner coordination sphere of the cesium are carboxylate oxygens while one is an oxide

ligand from an uranyl (UO

22+

) group. The coordination of uranyl oxygens is not unique, 96 different

structures are known which include actinyl oxygens binding to metal centres other than the

actinide which they are doubly bonded to. The rubidium uranyl triacetate has been characterized,

it has a tetragonal cell (a= 13.840 Å, b= 13.840 Å and c= 27.570 Å), but sadly no coordinates are

present in the Cambridge database. Potassium uranyl triacetate has a six coordinate potassium,

the potassium is coordinating to carboxylate oxygens only (Serezhkina et al., 2010) (Figure 6).

The sodium uranyl acetate has six coordinate sodiums, these sodiums are being coordinated to

by carboxylate oxygens.

So it is unlikely that the cesium would have been removed from the fission products by this

sodium uranyl acetate formation. In September 1957 the cooling water supply to tank 14 failed,

Figure 5. The coordination

environment of the cesium in

cesium uranyl acetate. The

cesium is blue, the uranium

atoms are yellow, the oxygens

are red, the carbons are dark

grey and the hydrogens are

light grey.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 26 of 100

the contents of the tank overheated to 330–350°C (Jones, 2008). On the 29th of September at

16:20 (local time) an explosion occurred. The majority (90%) of the radioactivity was deposited

within 5 km while the rest of the radioactivity was dispersed by the north-northeast wind (Akleyev

et al., 2017). To my mind this accident is a cogent argument for not storing highly active waste in a

liquid or other easily dispersible form, I reason it is better to condition the waste into a glass or

other solid which is not easily dispersed. Another key lesson is that it is best to avoid an

accumulation of a mixture of fuel and oxidant which can overheat. I imagine some readers will

have heard of Dr Alex Comfort or might have read some of his work. He was famous for writing a

popular sex manual (The Joy of Sex), but it is noteworthy that as a youngster he seriously injured

himself while experimenting with explosives. From what I have learnt of this event he had made

the mistake of grinding a mixture of a fuel and an oxidant. Equally it is inadvisable to heat violently

a large amount of a fuel mixed with an oxidant. But it is clear that under some conditions a fuel

and an oxidant can be combined and reacted without explosion. For example a candle flame is a

reaction of oxygen with the air with a fuel. While the majority of the fuel might be in contact with

atmospheric oxygen it is far too cold to react, the warmth of the candle flame melts the wax. The

wax is then drawn up the wick and it is heated to generate the combustible vapours which then

burn in the flame thus forming light, heat and combustion products. It is clear that often a candle

flame is a reaction which is in a steady state.

Equally it is possible to react cyclohexanones or formic acid with nitric acid in a denitrification

process without the mixture exploding. By treating PUREX first cycle raffinate [a Highly Active

Liquor (HAL] with formic acid it is possible to destroy much of the nitric acid in the HAL. It is

important to note that in the nuclear reprocessing industry it is common to take the highly active

raffinate (HAR) from the first cycle of the PUREX plant and concentrate this down to form a smaller

volume of highly active concentrate (HAC). For example recently some Chinese workers have

described how they have been able to denitrify simulated HAR (Li et al., 2017), this step is needed

if they are to treat HAR with their TRPO process. The idea of the TRPO process is to remove the

trivalent transplutonium elements (such as americium and curium), the neptunium (Li, Chen, &

Wan, 2012) (Np) and the residual plutonium (Pu) in the HAR to form a waste which needs to be

isolated from humans and their environment for a shorter time (circa 300 years). The actinides (Pu,

Am, Cm, Bk, Cf) can then be disposed of in a separate smaller volume waste store built to a higher

standard than that required for the high level beta/gamma waste or they could be placed in a fast

reactor as fuel. The latter option will require the removal of the lanthanides from the trivalent

actinide fraction. In the work by Sun et al. it was found that zirconium molybdate formed during

the reaction, when the removal of nitric acid was greater they observed that tin, tellurium,

Figure 6. The coordination

sphere of a potassium in

potassium uranyl acetate. The

potassium is purple, the ura-

niums are yellow, the oxygens

are red, the carbons are dark

grey and the hydrogens light

grey.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 27 of 100

ruthenium, rhodium and palladium disappeared from the solution into the precipitate. Equally at

the ITU during the PARTNEW project a HAR formed by small scale treatment of a genuine fuel

dissolution liquor (MOX in PWR, 30 GW day/ton metal) was concentrated by boiling and the

addition of formic acid without anything untoward happening (Serrano-Purroy, Christiansen,

Glatz, Malmbeck, & Modolo, 2005). Normally sugar is combined with high level waste (Highly

Active Liquor) before it is converted by the vitrification process into the waste glass (Harrison,

2014). While sugar is well known to be a fuel and nitric acid is an oxidant this process is safe, the

reason is that large amounts of sugar/nitric acid mixtures are not allowed to accumulate. The

reason the sugar is added is to aid the denitrification of the HAL and to reduce the formation of

volatile RuO

during vitrification.

As the explosion was caused by the reaction of a rather special mixture of sodium acetate and

sodium nitrate, it can be concluded that a Kyshtym like accident is not going to occur in a high level

waste (HLW) tank farm associated with a PUREX plant. A while ago in Ireland a television drama was

made about a serious accident at Sellafield which released vast amounts of radioactivity from the

liquid HLW storage facility. In the drama, named Fallout by Raidió Teilifís Éireann, this release of

radioactivity resulted in the deposition of sufficient radioactivity in Ireland to require evacuation,

unrest in Dublin and widespread adverse health effects. The drama was criticized by Dick Roche

(Environment Minister) of Ireland. He expressed the view that implausibility of the scenario in the

drama played into the hands of the pro-nuclear lobby (Bradley, 2006) and that the drama depicted

Irish people as being barbaric (Anonymous, 2006). The Radiological Protection Institute of Ireland’s

chief executive (Ann McGarry) stated “the scenario envisaged in the programme is not realistic and

grossly exaggerates the amount of radioactivity that could reach Ireland”(RPPI, 2006). I think that

the lack of chemical fuel in the high active liquid wastes at Sellafield is the main reason a Kyshtym

like accident is impossible. Now back to the Kyshtym accident.

The main radionuclides released by the Kyshtym accident are listed in Table 4.

Recent examinations of soil samples taken from 4 km from the epicentre of the accident confirm

that the accident released far more

Sr than

137

Cs (Molchanova, Mikhailovskaya, Antonov,

Pozolotina, & Antonova, 2014). It is also noteworthy that the

Sr is more mobile in the soil than

the

137

Cs in some places while in others the two radionuclides seem to have similar mobility in soil.

Two explanations exist for this difference, either the nature of the soils differs greatly between the

locations or the chemical form of the fallout differs between the two locations. As the conditions

inside the tank represent an extreme version of a denitrification process and as the chemical

reaction responsible for the explosion is likely to have generated alkali it is quite possible that the

release was in the form of an aerosol of solid particles. This may account for the difference in the

mobility of the radioactivity in the soil.

It appears that much of the

137

Cs had been removed from the waste before it was placed in the

ill-fated tank, so far I have been unable to find a flow sheet for the processing of the liquor from

fuel dissolution through to depositing into the tank. In the early days the Soviets were reported to

recovery radioactivity from the waste left behind from plutonium/uranium recovery. According to

Table 4. Main radionucldies released in the Kyshtym accident.

Nuclide Half-life Percentage Daughter Half-life

Sr 28.8 years 5.4

Y64h

Zr 64 days 24.8

Nb 35 days

106

Ru 373.6 days 3.7

106

Rh 30 s

137

Cs 30 years 0.35

137m

Ba 2.6 min

144

Ce 285 days 65.8

144

Pr 17.3 min

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 28 of 100

some Russian radiochemists (Milyutin, Gelis, Dzekun, & Malykh, 1995) several methods have been

used to recover cesium from reprocessing waste. These are coprecipitation with transition metal

ferrocyanides, coprecipitation with salts of heteropoly acids, solvent extraction with cobalt dicar-

bolide and adsorption onto transition metal ferrocyanides (Milyutin et al., 1995). The solvent

extraction process using a cobalt dicarbolide is known as the UNEX (Luther et al., 2006) is intended

for the removal of cesium, strontium and the actinides from high level liquid wastes. The cobalt

dicarbolide anion is a very large and poorly coordinating anion which has also found use in non-

radioactive and non-nuclear chemistry (Schweiger, Seidel, Arif, & Stang, 2002) (Figure 7).

Of the ferrocyanides tested (potassium nickel, potassium copper and potassium zinc) on silica

gel the potassium copper ferrocyanide performed best. The industrial process for the removal of

cesium is based on three reactions:

K2Cu3Fe2CNðÞ

12 þ2Csþ!K2Cu3Fe2CNðÞ

12 þ2Kþ

K2Cu3Fe2CNðÞ

12 !2eþ2CsþþCu3Fe2CNðÞ

Cu3Fe2CNðÞ

12 þ2eþ2Kþ!K2Cu3Fe2CNðÞ

Strong “nitric acid”is able to oxidize the solid, this oxidation might be due to the action of nitrous

acid and nitrogen oxides. Using hydrazine it is possible to reverse the oxidation. It is interesting that

rather than the Russian workers reporting a process in the literature during development or even

when it is at the pilot plant scale they were in 1995 reporting a process which had treated 8 million

cubic meters or waste and had recovered 24 MCi between 1988 and 1993. In my efforts to under-

stand the process I considered the solid state structures of copper ferrocyanides. A western group

(France, Spain and Mexico) have reported the crystal structure of K

CuFe(CN)

which is a layered solid

formed from cupric sulphate (CuSO

) and potassium ferrocyanide (Loos-Neskovic et al., 2004). This

clearly has anionic layers of a mixed copper/iron cyanide and layers of potassium cations. An

examination of the unit cell confirms that the empirical formula is K

CuFe(CN)

. This suggests that

the copper and the iron are both in the plus two oxidation state. This is a different formula to that

Figure 7. A cobalt dicarbolide

anion. The cobalt atom is blue,

the boron atoms are gold col-

our, the carbon atoms are dark

grey and the hydrogen atoms

are light grey.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 29 of 100

discussed in the Russian paper. This group stated that after being in contact with dilute nitric acid

that Cu

Fe(CN)

and other materials were formed (Figure 8).

In another paper (Ayrault et al., 1998) it has been reported that Cu

Fe(CN)

does absorb cesium

from 0.1 M nitric acid while Cu

Fe(CN)

fails to absorb cesium from this medium. However this

paper is spoiled by the fact that the equilibrium time for the latter solid was 5 h while that for the

first was 6 months. I would be more happy with the paper if the authors had measured the

adsorption of the cesium for both solids at the same time after starting the experiments. In this

paper it was found that copper can be released into dilute nitric acid as the cesium is absorbed.

The structures of Cu

Fe(CN)

and Cu

Fe(CN)

are similar to that of KNiFe(CN)

which is shown below

(Malecki & Ratuszna, 1999). It is important to note that the potassium sites are not fully occupied,

thus giving the impression that the unit cell contains more potassium than it truly does (Figure 9).

It is noteworthy that resins formed from KNiFe(CN)

and ammonium molydophosphate sup-

ported on polyacrylonitrile can be used for the separation of cesium from waters including sea

water (Kamenik, Dulaiova, Sebesta, & St’antna, 2013). This allows the cesium in environmental

water samples to be preconcentrated thus allowing the measurement of very small amounts of

134

Cs and

137

Cs. Such resins are being marketed currently by Eichrom. In common with the

cyanometallates ammonium molydophosphate binds the cesium by simple electrostatic

Figure 8. The structure of dipo-

tassium copper ferrocyanide.

Potassium atoms are pale blue,

iron atoms are green, copper

atoms are orange, carbon

atoms are dark grey and nitro-

gen atoms are dark blue.

Figure 9. The structure of

potassium nickel ferrocyanide.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 30 of 100

attraction. The cesium is absorbed by simple ion exchange. The anion in the solid is shown here

(Boeyens, McDougal and Van R. Smit, 1976). The anion has a phosphate at the centre of a

polymobdate cage (Figure 10).

While the Kyshtym accident did not involve a nuclear reactor it is an important accident as it

involved waste formed from nuclear fuel cycle operations. The Kyshtym accident is a difficult

accident to study in several ways, firstly it was hidden by the Soviet Union for many years and

secondly unlike Chernobyl and Fukushima the radioactive release occurred close to where several

other major releases had occurred. As a result the background of some radioisotopes in soil and

other media nearby is elevated. For example in 1967 during the summer the wind dispersed 20 TBq

Sr and

137

Cs from lake Karachay. While in the 1950s a vast amount of radioactivity (100 PBq)

was discharged into the Techa river in a combination of accidents and planned releases.

A series of accidents of the same general class as the Kyshtym accident have occurred in nuclear

fuel cycle sites, rather being induced by a surge by nuclear reactivity in or a loss of cooling of a

nuclear reactor, these are accidents in which an exothermic chemical reaction occurs which

scatters radioactivity in or around the plant. One recurring issue has been “red oil”, this is a poorly

defined substance which forms in PUREX plants. Red oil is formed when a mixture of nitric acid,

uranium nitrate, the organic diluent and tributyl phosphate is heated (Gordon, O’Dell, & Watkin,

1994). Red oil is thought to contain a range of nitro compounds which are able to decompose

exothermically on heating to generate gas. A series of red oil accidents in uranium active areas

have occurred in the USA, the most serious red oil accident so far occurred at Tomsk-7 on 6 April

1993. The accident involved a tank containing 4,000 l of nitric acid containing thorium (142 g),

uranium (8,773 kg), neptunium (248 g), plutonium (310 g), some fission products and some organic

matter. To this tank was added more nitric acid bringing the total to 21,000 l (Porfiriev, 1996). The

tank has been reported by Porfiriev to contain 537 Ci of alpha activity and 22 Ci of beta activity, but

I suspect that a typographical error exists in that paper which interchanged alpha and beta in that

sentence. The paper later states that the beta activity in the fallout was no more than 50 Ci. The

IAEA report on the event indicates that a total of 1.5 TBq (40.5 Ci) of beta/gamma activity was

released, according to the this report the total beta activity of tank contents was 20 TBq (541 Ci)

(Andreev et al., 1998). The IAEA report (Andreev et al.) stated that before the accident

8,757 ± 286 kg of uranium and 449 ± 120 g of plutonium were in the tank and that afterwards

8,707 ± 350 kg of uranium and 577 ± 117 g of plutonium were recovered from the wreckage of the

damaged equipment and cell. Thus it can be concluded that the majority of the radioactive

mixture remained inside the plant. In this accident a mixture of

Nb,

106

Ru,

Zr and

103

Ru with

small amounts of

137

Cs and

Sr were released. A small amount of radioactivity was detected in

Alaska (Larsen, Sanderson, Lee, Decker, & Beck, 1994), but the majority of the radioactivity was

Figure 10. The anion in ammo-

nium molydophosphate

[Mo

·PO

]

3−

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 31 of 100

deposited in the plant or close to the plant. It is noteworthy that the accident did not expose the

general public to large doses.

In July 1959 at an experimental sodium cooled reactor in the USA suffered an overheating

accident due to a leakage of tetralin (1,2,3,4-tetrahydronapthalene) into the sodium coolant. The

tetralin formed a solid which caused some blockages inside the core. A report by Jerry D. Christian

(expert witness in a 2005 court case) explains some of what happened. The uranium metal fuel

overheated while in contact with the stainless steel cladding. Christian pointed out that diffusion of

uranium into the stainless steel cladding and the 5% volume change caused by the alpha–beta

phase transition (663°C) of uranium caused the failure of the cladding on 13 out of 43 fuel

elements.

Alpha uranium is an orthorhombic solid (Eeles & Sutton, 1963), while beta uranium is a tetra-

gonal solid. As the two solids have different densities it is clear that when the phase transition

occurs that the volume of the uranium will change. Below are four different views of a unit cell of

alpha uranium, now while some of my readers will know instantly how to obtain the density from a

unit cell. I hold the view that very few things are “common sense”as to be common it would have

to be universal. For example a 14-year-old child who has grown up in Sweden will have (or should

have) a good understanding of how to cross the road safely but is unlikely to know how to deal

correctly with a poisonous spider, scorpion or snake. On the other hand a child who lives in some

remote part of Africa or Brazil with no motor traffic but plenty of poisonous creepy crawlies

hopefully will have a good working knowledge of how to recognize and deal with these creepy

crawlies but might not know how to cross a road (Figure 11).

To do this we first need to calculate the volume of the unit cell, in the case of alpha uranium it is

83.4473 Å

or 8.34473 × 10

−29

. The next step is to calculate the mass of the atoms in the cell.

We need to apply some simple rules when we see a unit cell with atoms in it. The unit cell is a

polyhedron with six faces (Table 5).

Figure 11. Four views of an

alpha uranium unit cell.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 32 of 100

We have two uranium atoms in the cell which are completely within the cell, so we have at least

two uranium atoms in the cell. The cell also has four uranium atoms which are touching only one

face. Thus we have four halves of a uranium atom from these atoms which appear in the picture of

the cell. As a result we have four uranium atoms in total. If the uranium is pure

238

U then we have

952 atomic mass units in the cell. As there are 6.02214 × 10

atoms in a moles of atoms we can

work out that we will have 1.580833391 × 10

−21

g of uranium in the unit cell. This is

1.580833391 × 10

−24

kilos. From the mass and the volume of the unit cell we can work out the

density will be 18.944 × 10

kilos m

−3

Christian argued that the diffusion of uranium into the stainless steel was able to form an iron-

uranium eutectic with a melting point of 725°C. An examination of the phase diagram of the iron-

uranium system reveals that two eutectic points exist (Chapman & Holcombe, 1984; Leibowitz &

Blomquist, 1991). Uranium and iron form several crystalline alloys which appear in the crystal-

lographic literature. These are Fe

U and FeU

(Baenziger, Rundle, Snow, & Wilson, 1950), the unit

cell of FeU

is rather complex it is an example of what I would describe as “atomic fog”where the

number of atoms makes it difficult to visualize the overall structure. The cubic Fe

U is somewhat

easier to understand it is a layered solid (Figure 12).

I reason that the formation of an iron/uranium alloy will assist in the melting of the cladding and

some of the fuel. It is interesting to note that almost all metals will form alloys with mercury. The

only common metal which does not do so is iron. I have always held the view that the best

container to put a bottle of mercury inside as an overpack is a carbon steel jar. My reasoning is that

if the inner container breaks that the carbon steel will be better able to resist the action of the

mercury than stainless steel or aluminium. In some ways plastic is a reasonable overpack for

mercury containers, but neither plastic or carbon steel is perfect. Given time plastics can become

brittle while carbon steel will rust when exposed to water and air.

The chemistry of some of the other elements in a typical stainless steel with uranium is more

complex. Wilson et al. report that nickel forms U

Ni, UNi, UNi

and UNi

. They were unable to work

out the structure of UNi. The crystal structure of U

Ni is the same as that of U

Fe while UNi

has a

Table 5. Summary of rules for counting atoms in unit cells.

Atom location Number of cells the atom is shared between

Inside the cell not touching any faces 1

Touching one face 2

At the edge of the polyhedron (touching two faces) 4

At a corner of the polyhedron (touching three faces) 8

Figure 12. The layers in Fe

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 33 of 100

different structure to UFe

. The UNi

structure is the same as that of MgZn

. A unit cell of this solid

is shown in Figure 13.

The UNi

has the same structure as AuBe

and PdBe

(Figure 14).

Noël and some other French workers have suggested that UNi does not exist but some solids with

empirical formulas close to UNi exist. These include U

and U

(Perricone, Potel, & Noël, 2002).

The crystalstructure of U

is another example of “atomic fog”. Here it is in all its glory (Figure 15).

Nickel forms another crystalline solid UNi

, which has the same structure as CaCu

. In this solid

uranium atoms partly replace nickel atoms at two crystallographic sites (Perricone & Noël, 2002).

In the following diagram the sites which are uranium atoms (and nothing but uranium) are at the

corners of the unit cell (thus we have 1 uranium). The green atoms on the top and bottom face of

the cell are sites which are occupied 97.5% of the time with nickel atoms and 2.5% of the time

with uraniums. Thus we have 0.05 uraniums and 1.95 nickels from these “green”sites. The blue

sites are occupied with nickel atoms 95% of the time and uranium 5% of the time. Thus from these

nickel sites we have 2.85 nickel atoms and 0.15 uraniums. Overall we have 1.2 uranium atoms and

4.8 nickel atoms. Overall we have a 1:4 ratio of uranium to nickel (Figure 16).

What we should understand is that when stainless steel clad uranium metal fuel is overheated

that the fuel will be able to interact with the cladding. It might have been better if the reactor had

contained a fuel with cladding which is less able to interact with it. One option would have been to

use a cermet fuel with a metal which is unable to reduce uranium dioxide to uranium metal.

Rather than releasing iodine in the form of elemental iodine, Christian argues that it would have

been present in the fuel in the form of uranium(III) iodide, cesium iodide (CsI) or another metal

Figure 13. A unit cell of UNi

the nickel atoms are in green

while the uranium atoms are in

yellow.

Figure 14. A unit cell of UNi

the nickel atoms are in green

while the uranium atoms are in

yellow.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 34 of 100

iodide. He pointed out that the yield of cesium atoms as a result of fission would be greater than

that of iodine. He argues as a result that the iodine will be immobilized in the fuel as cesium iodide

once the fuel has reached a thermodynamic equilibrium. I have considered this idea. If we assume

that the only nuclear processes in the core are nuclear fission (of

235

U) and the radioactive decay

of short lived fission products then from the fission yield of

235

U with 1 MeV neutrons of the long

lived nuclides we can estimate the I:Te:Cs ratio to be 1.0:2.4:17.6. Thus if all the tellurium is in the

form of cesium telluride and all the iodine is as cesium iodide then the fuel will contain Cs

Te, CsI

and Cs metal in a mole ratio of 2.4:1.0:6.2. Thus 28% of the cesium is present as Cs

Te, 6% as CsI

and 67% as cesium metal (Table 6).

Christian argues that if the fuel was oxidized to that barium, strontium, lanthanum, cerium and

neodymium in that order would sequester the iodine as metal iodides. If these fission products

were to be consumed by oxidation then the iodine would be absorbed as uranium(III) iodide (UI

Figure 15. A unit cell of U

the nickel atoms are in green

while the uranium atoms are in

yellow.

Figure 16. A unit cell of UNi

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 35 of 100

The first metal which the fission product iodine encounters will be uranium, thus it will form a

uranium iodide which can then later react with more electropositive fission products to form the

thermodynamically favoured iodide according to a reaction like this.

UI3þ3Cs !3CsI þU

Christian pointed out that if elemental iodine (I

) had formed then it would have been very likely

to react with the cladding of the fuel to form metal iodides such as CrI

, MnI

, FeI

, NiI

or MoI

.In

a French study it was found that even without oxygen being present elemental iodine is corrosive

to stainless steels (SS316 and others) (Aubert, Calais, & Beuze, 1975). In this study isothermal and

temperature gradient experiments were conducted. In the isothermal study a series of zones were

found on the surface of a sample of a low chromium 2574 stainless steel which had been heated

at 700°C with iodine (Table 7, Figure 17).

Likewise when SS316 is heated with iodine a manganese and chromium depleted zone is

formed on the surface. Christian also argues that any iodine which escaped from the fuel

would have been converted into the very involatile sodium iodide. He cited a report by

Castleman et al. which indicates that when a small amount of cesium iodide is combined

with excess sodium that it is converted into cesium metal and sodium iodide. The sodium

iodide is soluble in molten sodium, as the temperature of the sodium increases the solubility of

sodium fluoride, chloride, bromide and iodide increases (Bredig, Johnson, & Smith, 1955). A

further study using

Na,

132

Te,

131

Iand

134

Cs has confirmed that iodine and tellurium are

retained in hot sodium, when hot sodium containing was kept in a stream of helium gas the

sodium (

Na) was lost at a higher rate than

132

Te or

131

I from the sample (Clough & Fraser,

1973). The paper by Clough and Fraser also concluded that if iodine was to be released then it

would be in the form of an aerosol with sodium metal. Tellurium (as

132

Te) was more difficult

to study, it was found to absorb onto the stainless steel surfaces of the equipment. When wall

effects were removed the results suggested that the tellurium was better retained by the

sodium than iodine. In this paper the relative volatility (α

) of the elements (E) was estimated

by gamma counting. The radioactivity (A) of the elements in the liquid and gas phase are

written as A

Eliq

and A

Egas

respectively.

Table 6. Half-lives and fission yields of cesium, tellurium and iodine.

Nuclide Half-life Fission yield (1 MeV non

235

125

Te Stable 7.09115 × 10

−4

128

Te 7.7 × 10

years 6.84540 × 10

−3

130

Te 7.9 × 10

years 1.93507 × 10

−2

127

I Stable 2.79110 × 10

−3

129

I 15.7 million years 8.27312 × 10

−3

133

Cs Stable 6.72991 × 10

−2

135

Cs 2.3 million years 6.57105 × 10

−2

137

Cs 30 years 6.20320 × 10

−2

Table 7. Details of the layers on a stainless steel exposed to iodine.

Zone Nature of layer

A No change

B Steel which is depleted of Iron, chromium and manganese. nickel and molybdenum remain

C Contains only nickel (less than zone B) and molybdenum (more than zone B)

D Chromium iodide, likely to be formed by condensation of CrI

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 36 of 100

αE¼AE gas

ANa gas



=AE liq

ANa liq



Their values for iodine, tellurium and cesium obtained by measurement of the rate of loss of

radioactivity from the furnace were 0.5, 0.35 and between 4 and 75. The cesium values are over a

large range, they stated that the cesium attaches to the stainless steel walls of the equipment

which can reduce the release of the cesium. The aerosol particles formed when the vapours from

the furnace were allowed to cool in a steel box (0.1 m

volume), when the

Na to

131

I ratio of the

aerosol particles was measured a value of between 0.55 and 0.7 was obtained for α

. However

using the measurements of the radioactivity of the aerosol the α

value was found to be between

0.03 and 0.05. They reasoned that the tellurium is not uniformly incorporated into the aerosol but

it is condensed onto cool surfaces first. They argue that this could either provide a useful trapping

process for tellurium or a means of producing finer aerosols. Christian further argues in favour of

the sodium cooled reactor, by pointing out the work of Hart et al. which indicates that the molten

sodium retained strontium, iodine and cesium.

The case for the retention of iodine released as elemental iodine into the sodium coolant is

strengthened further by the work of Kunkel et al. who released iodine vapour at the bottom of a

container of molten sodium. Very little of the iodine was able to escape from the surface of the

sodium thus demonstrating that the iodine was retained by the sodium metal. It is most likely that

the iodine reacted according to the following equation with the sodium.

2Na þI2!2NaI

In January 1961 a reactivity accident occurred in the SL-1 reactor in Idaho killed three men, this

accident was a steam explosion caused by a surge in reactivity. The surge in reactivity was caused

by some unknown event during servicing of the reactor. This accident can be regarded as a

miniature version of Chernobyl, but in this case the reactor building was able to contain the

majority of the radioactive inventory in the reactor. As this accident was so similar to the more

serious Chernobyl accident I will not discuss it in detail.

At Chapelcross in 1967 an overheating accident occurred in a Scottish Magnox reactor. It was

predicted (Macdonald, Ballard, Thompson, Goldfinch, & Orchard, 1977) in the 1970s that in the

event of a single channel meltdown in a Magnox reactor that all of the noble gases would be

released from the damaged fuel, 10% of the non-halogen volatiles, 1% of the halogens and the

mid-volatiles and finally 0.1% of the non-volatiles would be released into the coolant. However if

air entered the damaged reactor and caused a fire in a single channel then it was expected then

that 50% of the halogens, cesium, ruthenium and volatiles would be released, 5% of the other

mid-volatiles and 0.5% of the non-volatiles would be released (Table 8).

In 1977 in Czechoslovakia an accident occurred in a plant named A1 two separate accidents

occurred during the working life of the plant. The A1 plant was a carbon dioxide cooled and heavy

water moderated reactor (150 MWe). The fuel was uranium metal clad with a magnesium/

beryllium alloy. The purpose of the beryllium was to reduce the tendency of the magnesium

cladding to oxidize. When a clean magnesium surface is first exposed (12 l H

O) in ultrahigh

vacuum conditions to water at 77 K according to PES it becomes covered with an oxygen species

Cr, Mn, Fe, Ni, Mo δ Mn, δ Fe, Ni, Mo δ Ni, Mo

CrI2

ABC D

Figure 17. A diagram of the

layers on the surface of a

stainless steel exposed to

iodine.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 37 of 100

which is suspected to be Mg(OH)

(binding energy 533.5 eV) and a small amount of MgO (531.0 eV).

When more water (500 l H

O) is deposited on the surface then the main oxygen species on the

surface is water (535.1 eV). On warming the surface up to 100 K this water is converted into a

mixture of mainly Mg(OH)

and a small amount of MgO. As the sample is heated further to 210,

250 and 390 K more and more of the Mg(OH)

is converted into MgO (Fuggle, Watson, Fabian, &

Affrossman, 1975). It has been argued that when a clean magnesium surface is exposed to oxygen

that first chemisorption of oxygen occurs, which is followed by the formation of an oxide layer

which then becomes thicker (Shih, Liu, & Wei, 2007).

While it might be possible to predict the thermodynamic outcome of a reaction, it is impossible

with thermodynamics alone to predict the rate at which a reaction occurs. For the oxidation of

magnesium or another metal the PB ratio is important. The Pilling-Bedworth ratio is the ratio of the

volume of the metal and the volume of the oxide. In the case of magnesium as the relative density of

the metal is 1.74 (Busk, 1952), the density of the oxide (MgO, periclase) is 3.59 (Jay & Andrews, 1946)

and that of the hydroxide (Mg(OH)

brucite) is 2.37 (Isetti, 1965). It can be calculated that one mole

of magnesium has a volume of 13.97 ml, one mole of the oxide has a volume of 11.23 ml and one

mole of the hydroxide has a volume of 24.60 ml. Thus if the magnesium was to be oxidized to

magnesium oxide the volume of the oxide will be smaller than that of the metal. As a result of having

a PB ratio of 0.80 the oxide layer will have cracks in it. As a result oxygen gas will be able to gain

access to the surface and the metal will also be able to leave via the gaps in the oxide layer.

In the case of the aluminium containing magnesium alloy Shih et al. observed the existence of a

aluminium/magnesium oxide close to the corroding surface, if this is formed by the migration of

aluminium to the surface and then the formation of spinel (MgAl

) then we need to reconsider

the PB ratio for this alloy. The density of spinel has been reported to be 3.57 (Fischer, 1967). The

volume of one mole of the spinel will be 39.86. It can be reasoned that if a small amount of spinel

was to form in the surface layer and aluminium is able to migrate towards the surface then it

could help to seal the cracks. The addition of a small amount of beryllium to magnesium greatly

reduces the ease with which it oxidizes and ignites. For example two AZ91D alloys containing 5

and 10 ppm of beryllium were compared in one paper (Czerwinski, 2004). Alloy B had a far greater

resistance to oxidation than alloy A, it was argued that the difference was due to the change in

beryllium content (Table 9).

In the first accident (1976) a large amount of carbon dioxide leaked out and killed several

workers. The second accident (22 February 1977) was an overheating accident. Many of the details

Table 8. Groups of fission products in the prediction of the behaviour of magnox fuel during an

accident.

Volatiles Mid-volatiles Non-volatiles

Arsenic Antimony Barium

Bromine Cesium Germanium

Cadmium Gallium Molybdenum

Iodine Indium Niobium

Rubidium Ruthenium Palladium

Selenium Tin Rhodium

Tellurium Silver

Zinc Strontium

Technetium

Yttrium

Zirconium

Rare earths

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 38 of 100

were supplied to me by the Nuclear Regulatory Authority of the Slovak Republic. Due to an operator

error the silica gel used to protect the fuel during transport and storage was not removed correctly

from the fuel. The bag of silica gel burst open and the silica gel spilled onto the fuel, the operators

did not clean it completely from the fuel element. The fuel element with the silica gel was then

loaded into the reactor. The silica gel then prevented the carbon dioxide gas from circulating

properly through the reactor. This then resulted in overheating. If this had been the end of the

matter then it is likely that the reactor could have been saved. However the overheating caused

the heavy water moderator (21 tonnes) to leak into the gas circuit, this caused rapid corrosion of

the cladding on all of the fuel in the reactor. Steam can react with magnesium in the following

exothermic reactions:

Mg þH2O!MgO þH2

Mg þ2H2O!Mg OHðÞ

2þH2

As the system has a high concentration of carbon dioxide we need to consider the following

reaction. Thankfully during a thermodynamic assessment of the following reaction has been done

during an assessment of a fluidized bed incinerator (Denloye, Gasner, & Adamchak, 1984). This

reaction at 850°C (1,123 K) was reported to have a DG of 90.091 kJ mol

−1

. This suggests that during

an overheating event the magnesium oxide formed will not react with carbon dioxide to form

magnesium carbonate. Magnesium carbonate is less thermally stable than calcium carbonate.

MgO þCO2!MgCO3

I have been told that circa 150 kilos of loosened cladding and 100 kilos of used fuel were

distributed into the primary circuit. This caused a release of 3.7 × 10

Bq (100 kCi) from the

used fuel and 5.5 × 10

Bq (14.9 kCi) from the cladding into the primary cooling loop. Over the

next days, circa 360 Ci of noble gases and aerosols escaped from the plant and about 100 Ci of

liquid discharges occurred.

It is interesting that the security and fire protection company Chubb have published a film which

shows the effect of spraying water onto a pile of 100 g burning magnesium turnings, putting it mildly

the results are rather dramatic (Chubb, 2018). The A-1 accident resulted in dire contamination of the

primary coolant circuit and due to a steam generator fault the secondary circuit was contaminated.

The A-1 accident might offer an insight into what would have happened in a MAGNOX plant if a large

water leak had occurred from a steam generator into the carbon dioxide cooling circuit.

On 28 March 1979, an overheating accident occurred in the Three Mile Island plant, this was

largely due to poor design of the control room and a horrible error in the wiring of the plant. These

both contributed to the operators of the plant misunderstanding the situation which resulted in

incorrect actions being taken. As a result of an event in a non-nuclear part of the plant (water feed

to the steam generators) provoked an emergency shutdown (SCRAM) of the reactor in unit 2. As

planned the control rods inserted and the nuclear reaction was stopped. What should have

happened was that a pressure release valve on top of the pressurizer should have opened for a

moment after the SCRAM to release some steam. Instead the valve opened and then jammed

open. The problem was that the indicator light for this valve in the control room showed the

intended state of the valve rather than its real condition. A second indictor lamp which could have

alerted the operators to the fact that the valve was stuck open was hidden from their view by a

poor design of the control room.

Table 9. Two magnesium alloys, the amounts of elements are in % (w/w).

Alloy Mg Mn Si Ni Cu Zn Fe Al Be

A Balance 0.34 <0.005 0.005 <0.001 0.59 0.002 8.94 0.0005

B Balance 0.25 0.012 0.0006 0.003 0.69 0.003 9.24 0.0010

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 39 of 100

Some other issues in the design of the plant contributed to the accident, for example the plant

lacked a sensor to measure the water level in the core. Such a sensor might have provided a

warning to the operators which would have changed the course of the event. But with hindsight

everything is always clear.

In 1986 the Chernobyl accident occurred, as a result of a poorly planned safety experiment a large

reactivity surge occurred in a graphite moderated light water reactor. This reactor design had a

dangerous positive void coefficient when operating at low power. One of the design flaws was that

the moderator was not in good thermal contact with the fuel. If the fuel and the moderator had been

in intimate contact such as that found in a pebble bed reactor during the power surge as the fuel

heated up the temperature of the moderator would have increased. This would have increased the

temperature of the neutrons. By increasing the speed of the thermal neutrons the fission cross

section of the fuel would have become smaller thus limiting the size of the power excursion.

If we assume that a nuclear reactor is infinite in size and moderated then the neutron multi-

plication factor k

∞

which is defined as:

k¼Neutrons in generation n

Neutrons in generation n1

Can be calculated with a four factor equation:

k1¼ηfpε

Where ηis the number of neutrons generated per neutron capture in the fuel, for example if a

single thermal neutron when captured by the fuel always causes the release of three neutrons in a

fission event then the value of ηwould be three. In real systems we need to know the ratio of nγ

reactions and neutron induced fission events. If we know the capture (σ

) and the fission (σ

) cross

sections for the nuclide then we can calculate ηfrom these cross sections and the number of

neutrons released per fission event (n).

η¼ν

1ðþσg=σf



When thermal neutrons cause fission in the fuel, sometimes the fast neutrons induce fission

reactions in the fuel without first being slowed down (moderated). These extra fissions are taken

care of by a constant z.

For various nuclides large resonance peaks exist in the graph of σ

against neutron energy in the

epithermal energy range (1–10

eV), the probability that a neutron is able to avoid simple capture

in a ng reaction as it zooms around the core bouncing between moderator atoms is given the

symbol p.

The symbol fis for the fraction of thermal neutrons which avoid being captured in nuclei other

than the fissile fuel.

The boiling of the water in the fuel channels increased the reactivity of the reactor by increasing

the fraction of the fast fission neutrons which after escaping from the fuel which return to the fuel

after scattering off the graphite. It is during this scattering process that their excess energy is lost

in the moderation process.

At Chernobyl as the core started to heat up during the power excursion as the water boiled this

removed a neutron absorber from the core, thus increasing the value of f. Also the burning up

(destruction of xenon) in the core will have suddenly caused fto increase. These increases in f

would have caused k

∞

to increase. As a result of the power surge a steam explosion occurred, this

ejected about 3.5% of the fuel from the plant. It also ejected other materials such as graphite

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 40 of 100

blocks from the core. This ejection of materials from the core and the rearrangement of the core

caused by the explosion altered the geometry of the core. All the fission reactors I have heard of

are non-infinite in nature. From these reactors the loss of neutrons is important. We need to

consider the “effective multiplication factor”(k

eff

) where P

and P

are the probability that thermal

and fast neutrons do not leak out of the core.

keff ¼k1PtPf

I do not wish to discuss in great detail the equations for calculating the values for P

and P

, but by

increasing the surface area to volume ratio of a reactor the values of P

and P

will decrease.

Conversely by placing a neutron reflector around fissile material the values of P

and/or P

will

increase. In several criticality accidents neutron reflectors have caused otherwise subcritical

masses of fissile materials to become critical. For example the demon core which killed two people

(Harry Daghlian and Louis Slotin) in two separate and horrible accidents became critical due to

neutron reflectors being placed around it. The demon core was a sphere of the gallium-plutonium

alloy which is used in nuclear (fission) bombs. It would have been a solid sphere with a hole to

allow a neutron source to be placed at its centre.

The report (Harding et al., 1948) on the doses of radiation delivered to the people in the room

used neutron activation of human tissue as a method of determining the neutron dose. Both

and

Na in urine and blood plasma were considered as methods for determining the neutron

dose. The

P can be formed by at least three reactions:

31Pþn!32 P

32Sþn!32 Pþp

35Cl þn!32 Pþa

Due to the complexities of the biochemistry of phosphorus the report concluded that

Na was a

better radionuclide for estimating neutron exposure after an accident. One method of improving

the estimate of the neutron dose is for a person to wear a crisis dosimeter. One option is to wear or

carry an object which will undergo neutron activation for example the late John Pecket told me

that at Harwell he wore an accident dosimeter which included a vial of sulphur which would have

helped reconstruct fast neutron exposure in the event of a criticality accident. Another thing which

could be used would be hair (Lebaron-Facobs et al., 2007), fingernail and toenail clippings. These

parts of the body contain a sulphur rich protein which could be examined for radioactivity (

P).

Using longer lived radionuclides it is possible to reconstruct neutron doses from the atom bombs

dropped on Hiroshima (Marchetti & Straume, 1996). Due to the great differences in design the

neutron to gamma ratio at Hiroshima was higher than at Nagasaki. The bomb dropped on

Hiroshima had a large amount of steel surrounding the highly enriched uranium, this would

have adsorbed gamma rays but allowed the fast neutrons to escape with ease. The Nagasaki

bomb had a plutonium core which was surrounded with plenty of organic matter (explosives)

which would have adsorbed neutrons but would have been transparent to gamma rays. A review

(Ainsbury et al., 2011) of the methods which can be used for retrospective dose estimation was

published recently so I will not dwell further on this topic.

A survey of early film badge dosimeters was made by the journal Nucleonics back in 1955

(Anonymous, 1955), if you want to look at an on line museum of dosimeters then Oak Ridge

Associated Universities has a very good one (Oak Ridge, 1999). But now back to the Chernobyl

accident.

Due to a defect in the design of the control rods of the RBMK reactor at Chernobyl an attempt to

SCRAM the reactor during the accident has been suggested by some to have been the event which

started the power surge. It is not clear if the control room workers attempted to SCRAM the reactor

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 41 of 100

before the power surge or if the workers pressed the SCRAM button after the power surge occurred.

At Chernobyl the control rods had graphite tips, thus as they were inserted at first they would have

replaced water with graphite rather than replacing water with a neutron absorbing material.

According to Landeyro and Buccafurni the RBMK reactor had four types of control rod, these

were manual, emergency, automatic and local automatic (Landeyro & Buccafurni, 1991). The

manual and emergency control rods had graphite containing displacers attached. These would

have displaced water from the channels where the control rods went. The graphite containing

displacers were separated from the adsorbing section of the control rod by 1 m. Landeyro and

Buccafurni used as a starting model a reactor which is not homogenous, they argued that the

“positive scram”effect of the insertion of the control rods was small compared with the effect of

the formation of voids in the reactor.

I reason that if an attempt was made at a SCRAM that for a moment that graphite displacer

section would have increased the reactivity in the lower part of the reactor. In the following

diagram the graphite displacer sections are shown in grey while the boron carbide containing

neutron absorber sections are shown in black. At the far left the arrangement of the control rod

when it was fully withdrawn is shown and on the right it is fully inside the reactor. When I saw

withdrawn and inside I am making a reference to the neutron absorbing section of the rod. As the

rod moves from the fully withdrawn position to the fully inserted position the graphite section will

for a time increase the moderation in the lowest part of the core (Figure 18).

It is important to keep in mind that the neutron flux in a reactor is not constant throughout the

whole of the reactor, a simple case is a reactor which is an infinite slab of thickness H. For this

reactor the flux distribution in reactor will be given by the following equation where distance z

from the centre of the slab. Here H

is a thickness which is slightly larger than the thickness of the

slab, this is due to the factor that some neutrons will leak out of the reactor.

ϕr;zðÞ¼A0cos πz

Hex



HHHHHH

LL LL L

Figure 18. A diagram of the

Chernobyl core and the control

rods. Hare the areas of the core

with the highest K

∞

due to the

lowest burnup, M are areas with

medium K

∞

and Lare the areas

with the lowest K

∞

. The boron

containing adsorbing sections

are shown in black and the

graphite displacers in grey.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 42 of 100

If we assume that the reactor has a cylindrical shape (height Hand radius R) then the axial and the

radial neutron flux distributions are given by the following equation if we assume that the neutron

flux is zero at the surface of the reactor. The Jis for the zero order Bessel function of the first kind.

ϕr;z

ðÞ

¼A0J02:405r

Rex



cos πz

Hex



For a reactor which is box shaped (parallelepiped) which has the dimensions 2X,2Yand 2Zthe flux

distribution at a point x,y,z from the centre of the reactor will be given by:

ϕx;y;zðÞ¼A0cos πx

Xex



cos πy

Yex



cos πz

Zex



According to Buki and Bede (1965) the flux distribution in a spherical reactor of radius Rat a point

distance rfrom the centre will be given by:

ϕrðÞ¼ A0sin πr=Rex

ðÞðÞ

We can continue with our geometric fun, by considering a sphere (R) with a central cavity (r

). The

equation for this system for the flux density is not quite so easy. For a spherical reactor with no

cavity the geometric buckling Bis given as.

Bg0¼π

The total volume of the sphere (active part and cavity) is given by the equation:

V0¼4πR3

The relationship between B

for the simple sphere and B

for the sphere with the hollow (which

has volume V) can be worked out by rearrangement of the following equation:

V¼1R0



Bg0



Which we rearrange into:

Bg0



¼V



1r0





As Vfor this reactor is given by:

V¼4π

3R3r03



We can write:

Bg0



¼4π

4π

R3r03



1r0





Then

Bg0

Bg ¼ﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ

R3r03

ðÞ



1r0





As expected the sphere reactor has a greater and greater geometric buckling value as the size of

the cavity inside increases. Within the central cavity the neutron flux is constant at the same value

) as at the edge of the cavity (r

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 43 of 100

ϕrðÞ¼ C1sin Bgr



þC2cos Bgr



The ratio of C

to C

can be calculated from the ratio of r

to Rusing the following equation:



¼ sin BgR

cos BgR



Buki and Bede also consider cylinder shaped reactors with axial holes and longitudinal holes. For

the reactor which is a cylinder of active matter with a coaxially arranged cylindrical cavity (long-

itudinal cavity) and the reactor with a cylindrical cavity at 90° to the axis of the main cylinder

which passes through the centre of the cylinder the equations are rather complex. For the coaxial

reactor the equation for the flux is.

ϕr;zðÞ¼C1J0αrðÞðÞþC2Y0αrðÞðÞ½cos πz



The ratio of C

to C

changes as a function of the value of r

/Rand the constant achanges as a

function of the overall radius (R) of the reactor. I will not discuss them further but I want my reader

to take away the message that in all practical homogenous reactors it is not possible to have a

neutron flux density which is uniform.

The fuel at the top and the bottom of the Chernobyl reactor had a lower burnup than the fuel in

the middle. As a result the fuel was more reactive. From the point of view of a reactivity accident

the worst part of the core in which to add voids or increase moderation was the bottom or the very

top of the reactor. While defect in the control rods did increase the reactivity in this part of the

reactor but Landeyro and Buccafurni reason that the void formation made a greater contribution

the power surge than the control rod defect. They also considered a second reactivity surge which

was caused by the fragmentation of the fuel.

In the 2015 review I commented on the origins of the term SCRAM. I would like to thank Jerry

Christian who brought to my attention a paper on the history of the term SCRAM. This paper (Murray,

1988) identifies Norman Hilberry as the axe wielding man who was ready to cut a rope which would

have caused a rapid insertion of a control rod. In the designs of the experiment the term SCRAM

(Safety Control Rod Ax Man) was present. I would conclude that the Chernobyl accident was caused

by a combination of the poor design of the reactor, errors made by the operators and also a failure of

the regulatory body to ensure that the reactor was constructed and operated in a safe manner.

In 2011 the Fukushima accident occurred, this was an event caused not by an event inside the

nuclear site but by an event (earthquake) outside the site. What happened was that an almighty

earthquake shook Japan making buildings shake, this earthquake also caused a very large tsu-

nami. The earthquake and the tsunami caused almost 30,000 people to die or disappear

(Takewaki, 2011). The earthquake also triggered units 1, 2 and 3 at the Fukushima Daiichi plant

to SCRAM. The other units (4–6) there were not in operation when the earthquake occurred. The

great problem with the Fukushima accident is that the accident was initiated by an event outside

the reactor site. Almost all serious radiological accidents before it have had an initiating event

which occurs within the nuclear site.

2.3. Forrest fires and other resuspension

One issue is the resuspension of long lived radioactive materials, here we are considering the

return of radioactivity into the air. The a wide range of potential events exist which can resuspend

radioactivity, one unusual event which was planned but never carried out was the “Divine Strike”

non-nuclear test planned at the former Nevada Test site. The “Divine Strike”was to have been a

large non-nuclear explosion, to test the effects of a “bunker buster”which would have occurred on

land which had been previously contaminated by nuclear bomb tests.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 44 of 100

Less dramatic events include forest fires in the area which was strongly contaminated by the

Chernobyl accident and the collapse of buildings. While the collapse of any radioactively contami-

nated building could in principle cause a release of radioactivity, a collapse of the Chernobyl object

shelter (also known as the sarcophagus) was of great concern. If the object shelter had collapsed it

could have released a large amount of radioactive dust, this possible event was one of the motiva-

tions for the construction of the arch which further protects the radioactive wreckage at the site. An

even less dramatic event is the driving of a vehicle along a road or agricultural management work.

Such activities can increase the amount of dust which is present in the air. It has been shown that

grass cutting in the Chernobyl exclusion zone (Zapolie 14 km from the reactor) causes a small

increase in the

137

Cs level in the air compared to that observed while equipment was being

assembled (Garger, Paretzke, & Tschiersch, 1998). However harrowing and driving trucks causes a

far greater increase in the

137

Cs level in the air. It is important that people be able to work in the

exclusion zone, trucks need to be driven to deliver supplies, fire prevention work needs to be done

and also decontamination work will sometimes need to be done.

Measurements made in the 30 km exclusion zone around Chernobyl between September 1986

and June 1993. The measurements were made at Pripyat (close to the reactor site) and at

Zapolie. It was found that even without obvious human dust raising activities that the air still

contained radioactivity which had been released by the reactor accident. During 1992 and 1993

soil samples were taken at Zapolie and it was found that the specific activity (Bq g

−1

)of

137

Cs in

soil increased greatly as the particle size was reduced while for

144

Ce little difference in the

specific activity of different size fractions was observed (Garger, Kashpur, Paretzke, & Tschiersch,

1998). As a result it can be concluded that the cesium is able to spread in the finer dust from soil.

It was also found by Tschiersch et al. that in 1986 at Zapolie that the majority of the

137

Cs and

144

Ce were in the form of coarse particles (>10 μm) while in later years the contribution due to

finer particles becomes more important. The fraction of the radioactive ruthenium (

106

Ru) pre-

sent in 1986 as finer particles is far greater suggesting that the ruthenium behaved differently in

the accident.

The reduction in the size of the cesium bearing particles can be explained by several hypotheses,

firstly the fixing of the larger particles without the generation of any new smaller particles will

cause the average size of the cesium containing particles to become smaller. Secondly if the

particles of cesium from the reactor accident are subject to a leaching reaction which releases

cesium which then is deposited onto small clay particles. These small clay particles (colloidal

particles) are mobile both in soil and can be resuspended with ease.

This reminds me of the fractionation of radionuclides which occurs in the moments after a

nuclear bomb detonation in the atmosphere. Those radionuclides which form solids in the seconds

after detonation tend to be present in finer solids than those radionuclides which were present at

the start of the particle formation time as volatile substances.

It has been found that the behaviour of a radioisotope in fallout depends on the chemical and

physical state of it about 20 s after detonation as the fireball cools and the fission products

condense, For example if we consider the isobars 95, 131 and 137 then the physical forms of

the fission products 20 s after detonation will be very different. All of the

Zr will be inside the

solid particles formed soon after detonation, while part of the

131

I will be found in these quickly

formed particles while almost none of the

137

Cs will be in these particles.

To do this we need to start with the yields for each fission product and their half-lives (Table 10).

As the yield of

131

In is so small and its half-life is so short we can ignore it. We start by

calculating the decay of the

131

Sn, tin will form an involatile oxide when heated to a high

temperature in air. So any of the atoms in isobar 131 present as tin at 20 s post-detonation will

be in an involatile form.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 45 of 100

Fractionation has been observed during studies of fine particles of fallout collected by a Swedish

jet aircraft far from Soviet thermonuclear tests. In the Swedish study particles were collected on a

filter, using autoradiography the larger particles were identified and separated. The larger particles

and the smaller particles were then gamma counted. It was found that with increasing time the

larger particles were no longer found, and that the fraction of

103

Ru present in the larger particles

was smaller than the fractions of

Zr and

141

Ce which were in the larger particles (Edvarson, Löw,

& Sisefsky, 1959). This can be explained by the fact that during the important condensation time

the majority of the fission products with an atomic mass of 103 will be in the form of

103

Mo.

Molybdeum forms a volatile oxide (MoO

), on the other hand 20 s after the detonation

Y and

141

Ba will be the main nuclides for the fission product decay chains in the isobars at 95 and

141 amu respectively. Both barium and yttrium oxides are involatile refractory solids (Tables 11

and 12).

103Zr !103 Nb !103Mo !103Tc !103 Ru

99Y!99 Zr !99Nb !99 Mo

There is a problem, while the Bateman equations might appear to be an attractive way of dealing

with these problems there can be a problem. The problem relates to the dynamic range of a digital

Table 10. Fission yields for nuclides with a mass of 131.

Nuclide Direct fission yield Total fission yield Half-life

131

In 3.12552 × 10

−5

3.12977 × 10

−5

0.28 s

131

Sn 1.35806 × 10

−3

1.39306 × 10

−3

56 s

131

Sb 2.22171 × 10

−2

2.74284 × 10

−2

23 min

131

Te 2.88969 × 10

−3

2.96379 × 10

−2

25 min

131m

Te 8.08651 × 10

−3

1.12682 × 10

−2

30 h

131

I 2.92679 × 10

−4

3.86972 × 10

−2

8.02 days

N.B.: 22% of

131m

Te undergoes IT to

131

Te the remainder beta decays to

131

Table 11. Fission products with a mass of 103.

Nuclide Half-life Direct fission yield

103

Zr 1.3 s 5.11176 × 10

−3

103

Nb 1.5 s 3.41644 × 10

−2

103

Mo 67.5 s 2.77626 × 10

−2

103

Tc 54.2 s 1.17345 × 10

−3

103

Ru 39 days 4.25129 × 10

−6

Table 12. Fission products with a mass of 99.

Nuclide Half-life Fission yield

Direct Accumulated

Sr 0.27 s 4.70499 × 10

−4

4.70583E−04

Y 1.5 s 1.31204 × 10

−2

1.35900E−02

Zr 2.1 s 3.95308 × 10

−2

5.30263E−02

Nb 15 s 5.57615 × 10

−3

3.95130E−02

99m

Nb 2.6 min 1.12247 × 10

−3

2.02119E−02

Mo 66 h 1.13554 × 10

−4

5.98385E−02

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 46 of 100

computer. This problem is mentioned in the master’s thesis of Captain Logan J. Harr of the USAF

(Harr, 2007). He used the delightful words:

“catastrophic cancellation occurs resulting in a shrinking denominator which causes the loss

of digits of precision”

To describe what happens when two decay constants are similar in size

If we consider an eight bit system in which we want to subtract one decay constant from

another. If we have λ

of 200 (11,001,000) and λ

of 198 (11,000,110) then in our system we can

start with 200 and 198, by subtracting one from the other then we will end up with 2. If we were to

change to a 16 bit system which records 200 as 0100111000100000 (200 × 10

) and 198 as

0100110101011000 (198 × 10

) then any rounding errors which will occur during the subtraction

of one number from the other will be smaller. As a result the computer system will be better able

to accurately generate small numbers by subtracting one large number from another large

number. The problem with the method based on the Bateman equations is that these errors can

cause the vast errors in the calculated activity. To explain this problem we can use excel or another

spreadsheet system. Place the top left cell in cell A1 (Table 13).

If the number in box b1 is increased then the error value in B8 should increase.

As a demonstration of this problem we can consider the decay chain

131

In →

131

Sn →

131

Sb →

131

Te. If

we consider the effect of reducing the dynamic range of excel by adding an additional term Qto the

Bateman equations we can quickly see the effect. For the third radioisotope in a chain we normally

write:

Ac¼AAλBλC

eλAt

λBλA

ðÞλCλA

ðÞ



þeλBt

λAλB

ðÞλCλB

ðÞ



þeλCt

λAλC

ðÞλBλC

ðÞ



But we can write the following in place of the more conventional exponential parts of the equation:

eλAt

QþλB

ðÞQþλA

ðÞ

QþλC

ðÞQþλA

ðÞ



When time (t) is zero we should calculate A

to be zero, we will use this as the test of the

calculations. As the value of Qincreases the size of the error increased. I have defined the error

as the value using the following equation:

Error ¼ACQ

AC0



1

It is clear that as the value of Qincreases the absolute value of the error increases (Figure 19).

Table 13. Details of excel calculations used to test the dynamic range of the calculation

process.

Dynamic range effect number 1

Half-life 1 100 Days

Half-life 2 100,1 Days

Lambda 1 =ln(2)/b2 Days−1

Lambda 2 =ln(2)/b3 Days−1

l1−l2=b4−b5 Days−1

l1−l2=(b1 + b4)-(b1+b5) Days−1

Error =(b6−b7) −1 Days−1

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 47 of 100

After having used the Bateman equations to model a range of things, my advice is to try to limit

the number of steps along a radioactive decay chain that you model using these equations. For

example you could if you knew the neutron flux in a reactor consider the evolution of the

transuranium elements in the following series using the Bateman equations. This series can be

explained by neutron capture, beta decays and one alpha decay at the end.

238U!239 U!239Np !239 Pu !240Pu !241Pu !241 Am !242Am !242 Cm !238Pu

While with the perfect computer it could be done, due to the limits of the computer very quickly

along the line we will run into trouble. A better way to deal with the problem is to leave out the

short lived nuclides to try to reduce the length of the chain. For example one can regard the

radioactive decay of

239

Np as an extension of that of

239

U as long as you are willing to make a

sacrifice of the accuracy of the predictions in the first days after the reactor is started with fresh

fuel. I would suggest that modelling the following would be better for many purposes. Now the

238

Pu is nuclide 6 in the chain rather than nuclide 10.

238U!239 Pu !240Pu !241 Pu !241Am !238Pu

Using real data from nuclear bomb tests done in the USA, Hicks was able in the early 1980s to

write an exceptional paper in which this fractionation effect is explained (Hicks, 1982). Using the

following equation the enrichment of a radionuclide relative to a case where no fractionation

occurs (w

) can be calculation from the refractory to volatile deposition ratio (z) and a constant for

each fission product (r

wi¼1ri

ðÞþðz:riÞ

If a perfect fractionation of fallout occurred into volatile and refractory (non-volatile) fractions was to

occur then after 4 h the majority of the radionuclides which are responsible for the external gamma

dose would be in the involatile fraction. Such a total fractionation would require the formation of two

fallouts with zvalues of zero and infinity. While such an extreme fractionation is not possible it has

been shown by Hicks that the smaller a fallout particle, the further a location is from a bomb test and

the longer it takes for fallout to arrive then the higher the refractory to volatile deposition ratio (z)is.

One consequence of this is that the people who were close to the bomb tests would have been

disproportionately exposed to the refractory class of radionuclides. Using the logic of Hicks it can be

reasoned that if radioactive ruthenium was to remain in the gas phase longer after release from the

damaged fuel at Chernobyl than the cesium then it would be able to form smaller particles.

Lurid accounts have appeared that suggest that radioactivity from forest fires near to the

Chernobyl site poses a grave threat to people living far from the accident site. In particular,

1,00E-12

1,00E-11

1,00E-10

1,00E-09

1,00E-08

1,00E-07

1,00E-06

1,00E-05

1,00E-04

1,00E-03

1,00E-02

1,00E-01

1,00E+00

1,00E+00 1,00E+03 1,00E+06 1,00E+09 1,00E+12 1,00E+15

Error

Figure 19. The error on the cal-

culation as a function of Q.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 48 of 100

Yablokov, Nesterenko, and Nesterenko (2009) stated that “On 6 September 1992, radioactive

aerosols lifted by a strong wind from the 30-km Chernobyl zone reached the vicinity of Vilnius,

Lithuania (about 300 km away) in 5–7 h, where the

137

Cs concentration increased 100-fold”. The

great problem is what consequence does a short duration 100-fold increase in the

137

Cs content of

the air have on public health. This question has already been considered by Jargin (2011), he

argues that the amount of exposure of the public to radioactivity which escapes from the

Chernobyl area as a result of wind and fire is insignificant. An increase of the

137

Cs level in the

air in Vilnius did occur in September 1992, and as a result of a fire in 2002 the radioactive cesium

level in Vilnius did increase again. It is interesting that the chemical form of the cesium differed

between the 2002 and that which arrived in Lithuania in 1986 and 1992 (Lujaniene et al., 2006).

The cesium in 2002 was in the form of an anionic substance while much of the cesium in the other

2 years was in a cationic form. One reason might be that the 2002 cesium was absorbed onto

particles which when immersed in water become anionic.

We need to be careful as the mere detection of a substance does not mean that it is present at a

dangerous level. For example I have been able to detect radioactivity (

K) in a packet of low

sodium salt purchased from a supermarket. Additionally an excessive intake of copper is harmful

to both humans and cats, but some copper is needed to keep cats healthy. I have ashed dry cat

food, extracted the ash with nitric acid and then detected copper. My detection of copper in the cat

food does not automatically indicate that consumption of cat biscuits will result in copper poison-

ing in either cats or humans. Equally it is possible to harm yourself by drinking monumental

amounts of Earl Grey tea (Finsterer, 2002), but moderate consumption of Earl Grey tea is a

relatively harmless activity. Paracelsus stated back in the 16th century “Was ist das nit gifft ist?

alle ding sind gift/und nichts ohn gifft/Allein die dosis macht das ein ding kein gift ist”which is

German for “What is not poison? All things are poison and nothing [is] without poison”. His grand

statement has also been summarized as “Solely the dose determines that a thing is not a poison”

(Borzelleca, 2000).

The great problem which we face is that some things only exert an effect when the dose (or

concentration) is above a given threshold while any exposure to some other things has a finite

chance of inducing an effect. In the latter cases the clinical course of the effect is the same

regardless of the dose required to induce it but the probability of inducing the effect increases as

the dose increases.

One of the key problems is dose rate, it has been reported that in North Carolina that either 80 or

160 mmol of potassium chloride is used as part of the lethal injection protocol (Zimmers et al.,

2007). While I do not wish to discuss the morality of and other issues associated with capital

punishment here it is interesting to note that a 500 g packet of low sodium salt contains 330 g of

potassium chloride which contains about 4.4 mol of potassium ions. While if one was to consume

an entire packet of either normal or low sodium table salt in 1 h either by mouth or by intravenous

injection I am sure that it would induce a series of dire effects. But it is clear that if you were to

ingest the low sodium salt over a year, each day adding a little to your food then you would be

more able to tolerate the potassium chloride.

Experiments have been done in which wood and straw which the fate of cesium, chlorine and

iodine were investigated (Amiro, Sheppard, Johnston, Evenden, & Harris, 1996). Here it was found

that the hotter the conditions the greater the fraction of these elements which was liberated into

the air and the smaller the fraction of the elements which were found in the ash. The experiments

at Chalk river in Canada indicate that when contaminated vegetation is burnt that very little

strontium (

Sr) is released into the smoke, most of it remains in the ash. But the release of the

cesium depends greatly on the temperature of the fire and the nature of the vegetation (Zhou,

Rao, Corcoran, & Kelly, 2016). Forest and grassland fires have been lit in contaminated areas, it

was shown that resuspension of cesium, strontium and plutonium did occur. But only a tiny

fraction of the radioactivity on the land became airborne during the fire (Yoschenko et al., 2006).

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 49 of 100

Measurements have been made after the wildfires in 2015 which were close to Chernobyl

(Evangeliou et al., 2016). It is reported that the effective dose due to the resuspension of radio-

activity caused by the fire was small (up to 4% of

137

Cs/

Sr and up to 1% of the Pu in a forest fire

(Yoschenko et al., 2006)) but under some conditions a fire which involves radioactivity could have

more serious consequences. Many years a series of safety experiments on nuclear weapons were

performed by the British government in Australia. These were known as the minor trials, in one

particular experimental series (Vixen A) plutonium was exposed to motor fuel fires. In these trials

plutonium metal was exposed to petrol (gasoline) fires, during these trials relatively little of the

plutonium became airborne.

The source term of a plutonium fire accident can be determined with the following equation

which appears in a review on plutonium dispersion during fires (Kogan & Schumacher, 2008).

Q¼PuinventoryPufraction ARF RF LPE

where Pu

inventory

is the amount of plutonium at the site, Pu

fraction

is the fraction of the plutonium

which is involved in the fire, ARF is airborne release fraction, RF is the respirable fraction of the

release and LPE is the leak path fraction.

It is important to keep in mind that depending on the conditions in the fire, either a small or a large

fraction of the plutonium present will be released. Also the respirable fraction of plutonium can vary

according to the conditions. When plutonium is burnt in air under static conditions, such as a pool of

molten plutonium in crucible then only a small amount of the plutonium is released. But when droplets

of molten plutonium burn as they fall through the air a large fraction of the plutonium is released. The

accidental fires which involve plutonium metal are most likely to be nuclear weapon accidents but it is

possible in principle within the civilian nuclear industry for plutonium to be dispersed during an

accidental fire. The two scenarios within nuclear sites which I think are most important are fires

which involve solids such as plastics and cellulose or liquids such as the aqueous liquids or process

solvent in a PUREX plant. In their review Kogan and Schumacher offer Table 14 for plutonium in liquids.

For boiling aqueous liquids the following equation is suggested by Kogan and Schumacher.

Where Bis the boil off rate ranges between 0.0004 and 0.0011 l cm

−2

min

−1

. The maximum

value of ARF from this equation is 0.02.

log ARFðÞ¼22070 B13:38 þ1:043 107B2



2.4. Charcoal

Charcoals are used in the nuclear sector as absorbant materials in order to perform a range of

tasks, they are used in protective clothing, sampling and for treating gases before release from a

nuclear power plant.

Charcoal has been used in protective clothing for a long time, a first world war UK military

respirator (the small box respirator) used charcoal. The latest UK military respirator (General

Service Respirator) also uses a charcoal. While some interesting protective filters such as unlit

Table 14. ARF and RF values for plutonium compounds in fires.

Conditions ARF RF Comments

Simmering aqueous liquid (quiescent surface) 1.0 × 10

−4

1.0

Boiling aqueous liquid (disturbed surface) 1.0 Use the equation below for ARF

Heating dried plutonium nitrate 7.0 × 10

−4

1.0 × 10

−5

Combustible liquid (dissolved plutonium) 0.1 1.0

Combustible liquid (powder present) 0.02 1.0 Where possible use RF for solid

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 50 of 100

cigarettes (Kumana & Lemlich, 1974), zeolites (Ning, Qiu, Wang, Liu, & Chen, 2013) and mesopor-

ous silica (Hudson et al., 2004) have been suggested for respirators charcoal together with fine

filters is very common. Charcoal is used in many individual and collective respiratory protection

systems, individual protection refers to personal protective equipment such as an air purifying filter

respirator while collective protection refers systems such as the air purification system used to

supply purified air to a bunker or other shelter. The use of a purification system to prevent the

release of radioactivity or some other harmful substance to the environment is strictly speaking a

collective protection system. For example at Chalmers in the nuclear chemistry unit all radio-

chemical fumehoods are fitted with a HEPA filter to prevent radioactive dust leaving the fumehood

via the extraction system. An additional set of HEPA filters are present in a plant room on the floor

above the laboratory which would provide protection to the general public and the environment if

the HEPA filter on a fumehood was to fail.

A combination of a particle arresting mechanical filter and a pad of charcoal offers protection

against some airborne threats. These include some forms of radioactivity which can be present in

air. It is important to keep in mind that charcoal is not a panacea for all harmful substances in air.

It has been shown that DABCO is needed in a charcoal to remove methyl iodide from air, while for

the removal of elemental iodine from air no DABCO is needed (Wood, 1981). In many mines

(Gillmore, Phillips, Denman, Sperrin, & Pearce, 2001), some caves (Sánchez, de la Torre Pérez,

Sánchez, & Correa, 2013) and now in the Chernobyl object shelter (Ogorodnikov et al., 2009)

(known commonly as the sarcophagus) high concentrations of radon and its radioactive daughters

can be found. Gavin Gillmore at Kingston-upon Thames has suggested that industrial archaeolo-

gists should take care to avoid excessive radon exposure while working underground in places

such as disused mines (Gillmore, Gharib, Denman, Phillips, & Bridge, 2011). While it should be clear

that

222

Rn is formed by the alpha decay of

226

Ra present in the minerals in caves and mines, the

220

Rn (Thoron) at the Chernobyl site is due to the decay of the

224

Ra formed from the radioactive

decay of

232

U. A range of radioactive decays and neutron induced reactions in uranium and MOX

fuel form

232

U (Yamamoto & Okumura, 2014). While some of these reactions will be predominately

caused by fast neutrons (such as the n.3nreaction on

234

U), some of these reactions can be caused

by slower neutrons (such as the n.g. reactions of

230

Th and

231

Pa). While it might be harder to

remove radon from air than dust particles, it is possible to greatly reduce the lung dose due to

radon by removing smoke and dust particles which have absorbed radon daughters onto their

surfaces. Dust masks have been shown to intercept a large fraction of the alpha emitting radon

daughters from air (Wake, Brown, Trottier, & Liu, 1992), also it has been shown in uranium miners

that a synergy between cigarette smoking and radon exists (Saccomanno, Huth, Auerbach, &

Kuschner, 1988). It can be reasoned that the radon daughters are able to bind to smoke particles

and these particles are more likely to lodge in the lungs than radon daughters present in clean air.

During a reactor accident or other radiological accident the air can become contaminated with

radioactive aerosols and volatile radioactive substances. It is important to bear in mind that the

nature of the airborne threat will depend on the physical and chemical properties of the radio-

activity present. It is also important to consider the non-radioactive threats which might be

present in a radioactive (or potentially radioactive) environment. For example pathogens, asbestos,

lead, electrical hazards and confined spaces may exist in a building with suspected radioactive

contamination (SRP, 2011), it should be clear that it would be pointless to don a cumbersome

respirator, a heavy lead apron and a plastic suit to protect against radioactivity if the person then

comes to some other unfortunate end. For example one could fall from a great height, get heat

stroke or be attacked by a dangerous animal while performing the work.

In the event of an easily dispersed source being broken open during an accident it is possible for

respirable radioactive particles to be liberated or formed. For example

226

Ra, as radium sulphate, has

been inhaled after some accidents (Marinelli, Norris, Gustafson, & Speckman, 1953)ashas

227

(Newton, 1966). In the event of a radioactive source being melted in a steel scrap metal furnace

(Neuschütz et al., 2005)then

137

Cs tends to be found in the dust which comes out of the furnace with

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 51 of 100

the off gases and sometimes as well in the slag, while the actinides (such as plutonium) tend to

concentrate in the slag (Sappok, 1991). If a dust is raised during the handling of either a contaminated

off gas dust or slag then itis possible for workers to inhale radioactive dust. Here again a dust mask can

greatly reduce the internal dose which a worker is subjected to. It is noteworthy that

Co tends to

become incorporated into the steel, unless the product is cut up with flame cutting or some other

method which generates dust this radionuclide will be less able to become airborne. It is interesting

that authors of the paper about the inhalation of radium sulphate includes Marinelli, he was the

inventor of a very special beaker which is still used in a modified way. The original beaker was a glass

beaker with a central hollow glass tube projecting up from the bottom. The idea was that a GM tube

could be placed in the central tube where it is surrounded by the sample. The modern version of this

beaker is a plastic cylinder with a cavity in the bottom which fits over the head of a sodium iodide or

germanium detector. Again this is done to increase the amount of sample which can be placed around

the detector (Figure 20).

But back to reactor accidents, in the early weeks after a reactor accident the radioactive iodine

can pose an airborne threat to workers. It is important to understand that iodine is often present

both as particulate matter and in the form of volatile substances such as elemental iodine and

methyl iodide. Luckily iodine binds very strongly to charcoal (Reyerson & Cameron, 1936) while for

good protection against methyl iodide and the other volatile organic forms of radioactive iodine

the charcoal needs to contain some additives.

A classic method of taking samples of volatile organic compounds is to use a charcoal or other

porous material (Bianchi & Varney, 1993; Franco, Correa, Marques, & Perez, 2014; Ramirez,

Cuadras, Rovira, Borrull, & Marce, 2010) to collect organic compounds from the air before they

are introduced into a gas chromatography machine. These methods have been used for the

detection of halogenated compounds including vinyl chloride (Miller, Kane, Robinson, &

Whittingham, 1978) and the organochlorine compounds from a charcoal grilled chicken restaurant

along with a vast array of other organic compounds, some differences in the emissions from the

wood oven roasted piglet restaurant were noted (Alves et al., 2015). Returning to compounds

which are more relevant to serious nuclear reactor accidents it is noteworthy that natural methyl

iodide, ethyl iodide, chloromethyl iodide and other halogen compounds have been observed in the

marine environments (Yokouchi et al., 1997). In the study by Yokouchi et al. the volatile organics

were trapped on Tenax TA®which is a porous resin made from poly(2,6-diphenylene oxide). The

idea of natural methyl iodide might be a surprise to many, one might think that organohalogen

compounds are exclusively or mainly artificial, but this is clearly wrong. Gribble (1994,2003)

pointed out that a large number of natural organohalogens exist. Methyl iodide has a role in the

natural iodine cycle, it is formed in the sea. The methyl iodide is then converted in the air into

inorganic iodine compounds which then fall in rain onto the land. Lovelock, Maggs, and Wade

(1973) noticed back in the 1970s that methyl iodide was being formed in the sea. In recent years

methyl iodide was used as a pesticide in the Californian strawberry industry. The use of methyl

iodide in strawberry farming is an interesting tale.

Figure 20. On the left the origi-

nal Marinelli beaker with a GM

tube in the central cavity while

on the right is the modern ver-

sion with a solid state detector

in the cavity at the bottom.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 52 of 100

For many years methyl bromide had been used as a fumigation agent to kill unwanted organ-

isms in soil and to kill a range of pests. In some ways methyl bromide was a horrible choice of

reagent, it has no strong warning odour and it is also harmful to the ozone layer. The great

problem is that it is too stable in the lower atmosphere. It can reach the stratosphere where ultra-

violet light breaks it down releasing a bromine atom. The bromine atom then acts as a catalyst for

the degradation of ozone in a cycle similar to the ClO

cycle.

Br þO3!O2þBrO

BrO þO3!O2þBr

The idea of using methyl iodide was that it would have similar chemistry in soil, woodworm

infested wood and other materials which were to be fumigated. Methyl iodide has been shown

to have an antifungal activity which is better than that of methyl bromide (Hutchinson, McGiffen,

Oh, Sims, & Becker, 2000). The stability of it in the troposphere is low thus protecting the ozone

layer. For methyl iodide released at mid-latitudes the atmospheric lifetime is 13.6 days and the

ozone depletion potential is 0.017, interestingly the iodine replacement for Halon-1301 (CF

Br)

when released from mid-latitudes has a atmospheric lifetime of 5.0 days and an ODP (Ozone

Depletion Potential) of 0.008 (Youn, Patten, Wuebbles, Lee, & So, 2010). In contrast methyl

bromide has an atmospheric lifetime of 256 days and an ODP of 0.39 (Ko et al., 1998). Halon-

1301 has an atmospheric lifetime of 75 years and an ODP of 18.6 (Bernard, McGillen, Fleming,

Jackman and Burkholder 2015). While from the ozone layer damage point of view these two iodine

compounds are ideal replacements for the bromine compounds, things have not always worked

out well for the iodine compounds.

I will not be discussing the iodine firecontrol chemicals, it is interesting to discuss the use of

methyl iodide in farming. It is interesting to look at some of the arguments regarding methyl

iodide in fruit farming. For example, the pesticide action network issued the following comment

http://www.panna.org/pan-news/strawberry-fields-poisoned-forever:

“The state that supplies 90 percent of U.S. strawberries has approved a fumigant pesticide that

chemists are hesitant to handle in the lab. One more reason tobuy organic. While it is unlikely that

methyl iodide injected into strawberry fields pre-planting will wind up on or in the nonorganic

strawberries you buy at the store, rest assured those conventionally grown berries could be

teeming with other toxic compounds. That’s because many chemical farmers relyon a cocktail of

pesticides to help compensate for chemically destroyed soil quality. For example, according to

Pesticide Action Network’sWhat’s on my food? tool, which uses U.S. Department of Agriculture

(USDA) Pesticide Data Program numbers, 55 percent of conventional strawberries contained

residues of the fungicide Captan, a probable human carcinogen, according to the EPA.”

I will examine some of the statements in this comment.

The statement “chemists are hesitant to handle in the lab”is to my mind a scary sounding non-

statement, the problem is does hesitant mean. Some sloth like chemists might hesitate to do

anything in the lab or elsewhere. Also the chemist who stops and considers what they are going to

do in the lab

before they do it might be regarded as a hesitant person compared with a person

who just does whatever comes into their mind. I have a preference for students who stop and

think through what they want to do rather than just act on impulse and then have to live (or die)

with the consequences.

The statements “those conventionally grown berries could be teeming with other toxic com-

pounds”and “55 percent of conventional strawberries contained residues of the fungicide Captan,

a probable human carcinogen, according to the EPA”suggest that substances which are harmful

are present in strawberries, but they do not indicate that these substances are present in sufficient

amounts to be of concern. With the improvements which have been made over the years it is

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 53 of 100

possible to measure many harmful substances at concentrations far below those at which they are

harmful.

Susan Kegley gave her expert opinion https://www.youtube.com/watch?v=I4uK9Blj5ms (also see

http://sagri.senate.ca.gov/sites/sagri.senate.ca.gov/files/TranscriptFinal_Methyl_Iodide.pdf at a hearing

considering if methyl iodide should be licensed as a pesticide in California. She makes a series of claims I

will consider some of them. At 2 min she states that methyl iodide vapour can drift in the air, I have to

say she is right. Methyl iodide has a lifetime in the air which is measured in days thus allowing it to

migrate from place to place. At 4 min and 15 s she states that methyl iodide is a carcinogen, and a

proposition 65 carcinogen. The problem is that many things are carcinogenic, but not all carcinogens are

equally able to induce cancer. In California a law exists (prop 65) which requires a warning to be issued

even for carcinogens which have very weak carcinogenic effects. These include oestrogen in oral

contraceptive pills and an attempt was made recently to force Starbucks and other coffee houses to

label their coffee with this warning. As a result I hold the view that the Californians are bombarded with

warning which have little meaning. If we consider a sign for a dangerous animal, it might seem like a

good idea to mark the entrance to a crocodile pit with a warning. But if the same sign is used to warn us

about the presence of a scary looking (but harmless spider) and a domestic cat (it might scratch) then

the warning will lose its ability to protect us from crocodiles and other very dangerous animals. To me

the use of proposition 65 dilutes the message that methyl iodide is either a carcinogen or likely to be one.

At 4 min and 30 s she states that methyl iodide can cause spontaneous abortion in animals (in

humans this is known as miscarriage). But when reading the literature the link between methyl iodide

and foetal death is not clear. In rabbits it is possible to cause foetal death by exposing pregnant rabbits

to methyl iodide vapour (Sloter et al., 2009), but an injection of sodium iodide induced the same effects

in the foetus. The paper concluded that the methyl iodide caused foetal death by overloading the

foetus with iodide. To me this is rather different to methyl iodide killing the foetus, to me it is inorganic

iodide killing the foetus. The methyl iodide just happened to be the delivery mechanism for the iodide.

As stable iodine (potassium iodide) prophylaxis has been recommended for children and pregnant

women (Agopiantz et al., 2016) this suggests to me that a threshold dose of iodide is needed to cause

foetal death. The study using rabbits used 4 days of exposure at 25 ppm.I think that 25 ppm of methyl

iodide is a very high level which humans should not be exposed to.

Kathleen Collins https://www.youtube.com/watch?v=uhR-Y1MrHaI talked about how alkylation

agents can induce cancer, she also commented that she is not allowed to dispose of the compound

to the environment in any way (5 min and 40 s) and “way higher than all the radioactivity we use”.AsI

have no knowledge of what radionuclides she uses or the amounts I cannot make much of a

judgement on this matter, also without her being willing to give out details of what radionuclides

she has at her lab and the amounts (Sucha disclosure is inadvisable for nuclear/radioactivity security

reasons) it is impossible for anyone to make a judgement as to how bad the methyl iodide is compared

with her radioactivity. If she has 100 kBq of tritium then this is close to harmless, if she has 2 GBq of

131

then this is something to worry about more. Let alone the risks posed by 100 MBq of

238

Pu or

226

Ra.

At 6 min and 15 s she states that to use methyl iodide she would have to do a risk assessment

which would consider why she needs to use methyl iodide. I have to point this out but in both the

UK and Sweden the regulations on the use of chemicals in the workplace require me as a chemist

where possible to use less hazardous chemicals where possible. Thus methyl iodide should not be

regarded as being special in this way. Her comments about being not allowed to release the

compound are in some ways a bit of a red herring, while methyl iodide should not be released in a

wanton manner into the environment. It is possible by using tarpaulins, thiourea (Zheng, Papiernik,

Guo, Dungan, & Yates, 2005) and thiosulphate (Xuan, Yates, Ashworth, & Luo, 2012) to reduce the

escape of volatile alkylating agents from soil, what I found interesting about the campaign against

methyl iodide use in California is that it seemed to concentrate on the idea that “methyl iodide is

dangerous”rather than considering the questions of “can people work safely with methyl iodide?”

and “can we trust farm workers to work safely with methyl iodide?”

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 54 of 100

While for the measurement of an organic chemical such as benzene or vinyl chloride the

substance must be liberated from the porous material to allow it to be directed into a device

such as a gas chromatography machine to enable it to be separated and then measured, in the

case of a radionuclide which emits gamma rays it can be measured while it is still absorbed in the

charcoal (or other solid). The gas chromatography can be compared with the radiochemistry used

to purify radioactivity in an environmental sample into a form which can be measured. For

example one method for the measurement of plutonium in rainwater the plutonium is separated

using chromatography on ion exchange resin from iron before depositing the plutonium onto the

metal disks used in an alpha spectrometer (Montero & Sánchez, 2001).

When radioactive samples consisting of radioactivity absorbed onto charcoal are counted with

gamma spectroscopy, the charcoal is used to improve the efficiency of the counting by concen-

trating the radioactivity into a small volume. For example if a gamma emitter was dispersed evenly

throughout a cylinder which is 2 m in radius (Rs) and 4 m tall (h) then ignoring absorption effects

then the counting efficiency will be very low as the vast majority of the gamma photons will never

enter a modest sized detector. Using the equation (Aguiar, Galiano, & Fernandez, 2006) the

difference in geometric efficiency between the counting efficiency of the cylinder with a point

detector arranged coaxially at distance dfrom the circular surface of the cylinder is given by:

zt¼zpfgeo

where z

is the efficiency for the cylinder source, z

is the efficiency for a point source at d+(h/2)

from the detector, f

geo

is given by:

fgeo ¼2



hRs arctan dþh



þdþhðÞ

2Rs2ln 1 þRs2

dþhðÞ

þRs arctan d



d3

2Rs2ln 1 þRs2



Using this relationship, and assuming dto be 0.03 m, it can be shown that the geometric efficiency

is circa 60% of that of a point source which is placed 2.03 m from the point detector. While 60%

might not appear to be a bad efficiency, it is important to note that a point source 203 cm from the

detector will give a counting efficiency 841 times lower than a point source only 7 cm from the

point detector. Thus the cylinder of air (4 m high with a radius of 2 m) will give a 1,401 times lower

counting efficiency than the point source at 7 cm from the point detector. If the point source at

7 cm from the detector centre is replaced with a cylinder with a radius of 3 cm and 8 cm high

which has the detector on its axis (3 cm from the centre of the circular face of the cylinder), the

large cylinder will cause the detector to register 1,251 times fewer counts per second than the

large cylinder. Thus it should be clear that by concentrating the radioactivity from a large cylinder

of air into a small cylinder of charcoal then the measurement will be far easier.

In some cases separation of different elements using charcoal is possible, one problem in

nuclear reactors are the leaks in cladding of fuel. Despite the best efforts of the fuel makers

some fuel pins develop leaks during use. Charcoal can be used to improve the measurements of

the radioactivity which is leaking from the fuel. In the 1980s an interesting gamma spectrometry

experiment was done in Japan at a research reactor (JRR-3), here the helium cover gas over the

reactor was examined using a coal based charcoal (Sakai, 1984). One of the great problems in

gamma ray spectroscopy is that it can be hard to measure a low energy gamma emitter at the

same time as a high energy gamma emitter is present. One of the reasons is that the high energy

gamma emitter causes the background in the detector for low energies to become high as a result

of the Compton effect. Now here is a spectrum which I recorded recently using a large bottle of

. What you can see is a smile shaped curve to the left of the photopeak from the electron

capture decay of the

K (Figure 21).

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 55 of 100

This curve in the spectrum is caused by the Compton scattering process, what happens is that

gamma rays interact with electrons, they change direction when they strike electrons. As momen-

tum is conserved the electron accepts some momentum and energy from the gamma photon. The

fast moving electron tends to give up its energy in the detector while sometimes the product

gamma photon escapes from the detector. As a result only part of the energy of the photon is

delivered to the detector, as a result a wide range of different fractions of the energy of the original

photon can be delivered to the detector. This increases the background in the detector for low

energy events. It should be clear to the reader that the presence of a large amount of

Ar in

charcoal pad will make it hard to measure the low energy lines of nuclides such as

85m

Kr. Below I

have shown some of the key properties of some noble gas radionuclides which are formed in a

nuclear reactor (Table 15).

The

Ar is generated by the action of neutrons on

Ar (neutron activation) while the krypton and

xenon are formed by fission. As a result in reactors in which air cannot be excluded totally from the

system it is possible to generate some of this high energy gamma emitter. The measurement of free

fission gas levels in nuclear reactors can be used to estimate how much fuel has damaged cladding,

it is important to note that water cooled reactors tend to have a problem with “tramp uranium”.

Tramp uranium is uranium which was in the original water used to fill up the reactor or uranium

which has escaped from damaged fuel in the past, this tramp uranium can undergo fission in the

core and generate the radioactive fission products which include noble gases.

A small hole in a fuel rod can increase the radioactivity level of coolant, for example Lin and

Chao reported that before the leaks occurred in some fuel about 100 pCi g

−1

Sr and

Sr was

present in the coolant of a reactor, while only 1 pCi g

−1

131

I was present in the water (Lin & Chao,

2006). Around week 16 of cycle 16 a leak occurred which increased the

131

I level to almost

100

1000

10000

100000

0 500 1000 1500 2000 2500 3000 3500

Counts

Ener

(keV)

Figure 21. Gamma spectrum of

Table 15. Details of some noble gas radionuclides formed in a fission reactor.

Nuclide

85m

133

135

135m

138

Half-life (h) 1.82 4.48 1.27 2.84 126 9.14 0.255 0.237

Gamma lines (keV) 1,294 151 403 196 81 250 527 154

305 362 608 243

834 258

1,530 397

2,392

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 56 of 100

100 pCi g

−1

(the level of some of the other iodines

132

133

134

I and

135

I also increased slightly at

this time). But the

Sr and

Sr levels only increased months later. It can be argued that the

strontium can be used as a means of sensing a different fuel failure to pin holes which are

assumed to release the iodine.

To explain these changes we can use the empirical relationship which Lin and Skarpelos (1997)

reported that General Electric used:

Ai¼KYiλ1bior Ri¼Kλ1b

In their 1990s paper Lin and Skarpelos divided releases of fission products into the water of a BWR

into three classes, recoil (from tramp uranium b= 0), equilibrium (from pin holes b= 1) and

diffusion (split cladding b= 0.5). Here they came up with an equation for the release rate which is:

Ri¼KrþKeλ1þKdλ0:5

where K

and K

are constants which relate to the three different sources of the fission product.

Now if we subject uranium to a neutron flux (σ) and the fission yield (Y) for a given nuclide is known

then it will be possible to estimate the ratio of the radionuclides which will be present when the

reactor has reached equilibrium, for this calculation we will ignore neutron capture by fission

products. For iodine we get the following results (expressed as an activity ratio) when b=0.

For this ratio I have greatly simplified the calculations by assuming that the only formation of the

iodines is fission directly to the iodines, in reality the iodines are largely formed by the beta decay of

precursors such as

131

Te (t

=25min)and

131

Sb (t

= 23 min). While I havepresented data for iodine,

I could have presented data for any element formed in the fuel. The key thing here is that we are

looking at the ratio between short and long lived radionuclides (Figure 22).

The fission products released by damaged fuel, will give a different activity ratio. This is because

time is required for the fission product to be transferred out of the fuel and into the coolant. In the

event of an accident which did not cause damage to fuel the radioactivity release would be higher

as the coolant (heat transfer fluid) would be have a higher radioactivity level. An example of such

an accident would be a spillage of coolant. The degree of core damage can be estimated by taking

a sample of the water from a light water reactor and measuring the radioactivity level.

It should be clear to the reader that even if leaking fuel (damaged fuel) is unlikely to worsen a

serious accident it is not desirable to operate a reactor with leaking fuel inside it, now we have the

question of how does one find the damaged fuel in a reactor. While in theory one could unload all

the fuel into a hotcell (taking care to avoid a criticality accident) and examine or test it all for leaks,

it should be clear that this would be a slow, expensive and tiresome process. The reader will be

glad to know that there are better methods of checking fuel. One method is known as flux tilting,

I-131

0% I-132

18%

I-133

I-134

71%

I-135

IODINE RATIO AT THE POINT OF FISSION

Figure 22. Pie chart of the

iodine activity ratio at the point

of fission.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 57 of 100

the idea is that the reactivity of the reactor as a whole is kept constant, but by moving the control

rods it is possible to increase or lower the flux in part of the reactor.

As the tramp uranium which is in the water is still subject to the same neutron flux (on average)

the contribution to the coolant radioactivity from the tramp uranium will not change. But if the

release of radioactivity from a fuel pin changes as a function of the neutron flux it is subject to

(and thus its thermal power output) then the coolant radioactivity will then change. By performing

a series of flux tilting operations it is possible to eliminate many of the fuel assemblies from the

hunt for the defective one.

3. Other fission products and activation products

In the early days of the nuclear industry an atomic utopia was offered to the general public, in

some books from the 1950s it was promised that nuclear technology would offer us a far better

life. This was supposed to be a world of electricity too cheap to metre. However all was not to stay

well forever, events such as the contamination of the Lucky Dragon fishing vessel during the castle

bravo hydrogen bomb test in 1954 changed public opinion. While the castle bravo bomb was an

intentional nuclear detonation in some ways it was a nuclear accident. The reason I would

consider it to be an accident is as a result of an unexpected nuclear reaction. The neutron

bombardment of

Li instead of forming

Li (t

= 838 ms) which would decay via

Be to a pair of

alpha particles formed a tritium nuclei, an alpha particle and a neutron.

7Li þn!3Hþ4He þn

The more common reaction for the production of tritium is:

6Li þn!3Hþ4He

This addition of extra neutrons and tritium into the secondary of the bomb would have increased both

the amount of fusion which occurred and the neutron flux on the uranium tamper which is thought to

surround the fusion fuel. As the castle bravo event was a military accident (unexpectedly high yield) we

will leave it alone now. Together with other events in society the castle bravo event may well have made

the public less trusting of their governments and their representatives. It may be as a result in this lack of

trust in governments that the public have turned to other sources of advice and information. Sometimes

members of the public make some choices regarding information sources which are surprising.

Some of the people who the public trust make statements which cannot be reconciled with the

results of experiments, my advice on fission product chemistry is to be careful who you trust and to

where possible check the facts for yourself. Also be careful of those who might choose to

deliberately not tell the whole truth but only the small fraction of the truth which suits their

political purposes. For example Caldicott, (2006) wrote in chapter 3 of her book entitled “Nuclear

Power is not the answer”the following about cesium.

“Cesium 137 is an isotope with a half-life of 30 years, radioactive for 600 years. As a potassium

analogue, it is present in every cell of the body. Cesium 137 tends to concentrate in animal muscle

and fish, and it deposits in human muscles where it irradiates muscle cells and other nearby

organs. It is a dangerous beta and high-energy gamma emitter and is very carcinogenic”

I am now going to consider the following statements which I can extract from this short bit of text.

(1)

137

Cs has a half-life of 30 years;

(2) It is radioactive for 600 years;

(3) It is present in every cell of the body;

(4) It tends to concentrate in animal muscle and fish;

(5) It is very carcinogenic.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 58 of 100

I would agree that the half-life of

137

Cs is 30 years, but the idea that it is radioactive for 600 years is a

rather odd idea to me. After 600 years the activity of

137

Cs remaining will be about 9.5 × 10

−7

times

that which is present now. But in year 601 the activity will not suddenly drop to zero, thus it is

unreasonable to say it will be radioactive for 600 years. A better way of expressing the lifetime of a

nuclide is the “average lifetime”of the radioactive atoms which in the case of

137

Cs will be 43.2 years.

We have to ask ourselves the question of how much must be present for it to be in a cell, one of

the great problems is that with more and more sensitive measurement equipment it is possible to

detect things at lower and lower concentrations. The great problem is that since the nuclear bomb

tests everybody now contains a trace of

137

Cs along with wine. Gamma counting in an ultralow

background system has been used to detect some cases of wine fraud. One method of wine fraud is

to mislabel a new wine as an older (and more expensive one), Philippe Hubert has been using a very

low background high purity germanium detector to measure the tiny trace of

137

Cs in wines (Hubert,

Perrot, Gaye, Medina, & Pravikoff, 2009). Rather than trying to date wine using beta emitters such as

tritium (

H) and

C he has used a beta-gamma radionuclide as the measurement does not require

the bottle to be opened. In a paper he described how he uses an inner shield of very old lead (no

210

Pb), a layer of boron loaded polyethene, a layer of normal lead, another layer of boron loaded

polyethene. On the outside of this system some plastic scintillation detectors are used to veto the

germanium detector when cosmic rays strike the shielding. With this system it is possible to detect

137

Cs down to a few mBq per litre. The problem is that if it is possible to detect

137

Cs in many wines it

is reasonable to assume that in most people it would be possible to detect this nuclide if you were to

try sufficiently hard. However it is not reasonable to assume that the mere detection of

137

Cs will

render the wine dangerous to drink. Using the data in Prof Hubert’s paper and the assumption that a

wine glass holds 100 ml, I have calculated that a person drinking a Bordeaux from the height of the

cold war (1962) that get a dose of about 1.3 nSv from the cesium in the wine. At nuclear chemistry in

Chalmers this would correspond to about 4 s of background radiation. To reach the occupational

limit (1 mSv year

−1

) for radiation exposure for a non-radiation worker from this wine cesium, one

would have to drink a staggering 2,106 glasses of this rather expensive wine per day. I am sure the

alcohol will kill you long before the cesium! While this example might be somewhat bizarre it does

prove the point that mere detection should not be equated with danger. As a result I think that

statement three while being true it is of little note.

The idea that cesium tends to concentrate in animal muscle and fish can be considered. Some

evidence exists that in some food chains that cesium can become concentrated. By spiking a lake

with stable cesium (

133

Cs) and then following the cesium concentration in a series of different

animals the biomagnification of cesium was observed in two food chains (Pinder, Hinton, Taylor, &

Whicker, 2011). But inn a recent study it was shown in India that the concentration of

137

Cs in

grass is lower than that of the soil (Karunakara et al., 2013) (Table 16).

Also the grass to milk transfer coefficient was low, the following equation was used to calculate

the transfer coefficient (F

−1

), A

is the radioactivity of the milk (Bq l

−1

), A

is the specific

radioactivity of the grass (Bq kg

−1

) and Q

is the daily intake of grass (kg d

−1

FM¼AM

AgQM



Using two cows it was estimated that a cow eats 2.2% of its body mass per day, it was found that

cows which graze on common grazing areas have a F

value between 0.030 and 0.64, while cows

Table 16.

137

Cs activities in soil and grass in India.

Item or flow Cesium activity

Soil 1.1–25.7 (11.8) Bq kg

−1

Grass <0.05–5.3 (1.7) Bq kg

−1

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 59 of 100

from a dairy farm have a F

value of 0.050–0.15. The geometric means of these values are 0.12

and 0.092 respectively. These results suggest that cesium does not biomagnify through all food

chains. The dairy farm cows (Holstein Fried, commonly known as Jersey) produce 12–15 litres per

day. As the

137

Cs content of the milk from the farm was 0.04 Bq kg

−1

, we can estimate that the

cows release 0.48–0.60 Bq of radioactive cesium per day in their milk. As the cows ate 13 kilos per

day of grass (dry matter) they would have ingested 16.9 Bq of radioactive cesium per day. I

suspect that much of the cesium which each cow eats is excreted in the urine.

While much of the cesium in a human will be in the muscle tissue cesium has a relatively short

biological half-life in humans, thus I think it is unreasonable to state that “that it concentrates in

animal muscle”as this statement strongly suggests that it accumulates in this tissue. Observations

made on workers from the Chernobyl accident site indicated that a fraction of the cesium in a human

is retained (effective half-life 360 days) (Kutkov, 2000). This long retention time is very likely to be

due to the fact that the

137

Cs is within aerosol particles formed from spent nuclear fuel. Kutkov also

gives the ratio between six radionuclides which were found in workers at Chernobyl (Table 17).

After the accident in Brazil (Goiânia) in humans the fraction of cesium which is retained can be

approximated by the equation. Where a

= 0.15, a

= 0.85 and a

= 0.001. The constants k

and

are calculated from the half-lives of the three different pools of radioactivity 3, 90 and 500 days

respectively (Melo et al., 1997).

At¼a1ek1tþa2ek2tþa3ek3t

It is important to note that diet and other things can alter the biological half-life of cesium

(and I assume other elements). In sheep it has been shown that by increasing the amount of

potassium in the diet of sheep increases the rate at which

Kand

134

Cs is excreted. But a

change in the amount of sodium in the diet of the sheep has no effect on the rate of loss of

Kand

134

Cs (Mraz, 1959). It is also interesting that on average the biological half-life of

cesiumin27±8yearoldwomenis84days(ESD[EstimatedStandardDeviation]=27days)

while in pregnant women (25 ± 5 years of age) isonly49days(ESD=16days)(Zundeletal.,

1969). These papers on sheep and women are good reminders of several things, firstly the

habits and diet of an animal can alter the metabolism (and thus the biological half-lives of

elements). Secondly between different individuals there are some variations.

I hold the view that a good case exists for limiting the amount of radiation and radioactivity a

pregnant woman or child is exposed to. But if the biological half-life of cesium in pregnant women is

shorter then this may mitigate the consequences of an intake of radioactive cesium by women to

their children. It is also noteworthy that the in a study of 12 German women that it was found that

cesium is not reconcentrated in breast milk. Only circa 15% of a woman’s daily intake of

137

Cs in food

and drink is transferred into one litre of breast milk. While only circa 0.25% of a woman’s total body

137

Cs activity is transferred into the litre of breast milk (Gall, Mahler, & Wirth, 1991). Depending on

what part of the diet the radioactive cesium is delivered in under some conditions, such as radio-

cesium in drinking water, it may be possible for the breastfeeding woman to act as a filter which

reduces the intake of radioactivity by her child. This is compared to the scenario in which an infant is

fed baby formula which has been reconstituted with contaminated drinking water.

When lead is compared with cesium it is far clearer that lead accumulates in some organs (such

as bones). Using a compartment model for lead in human beings I have made some predictions

Table 17. Radionuclide ratio in workers at the Chernobyl accident.

Nuclide

106

131

134

137

141

Relative

amount

0.9 ± 0.2 3.6 ± 2.0 2.8 ± 3.0 2.5 ± 1.0 2.8 ± 1.5 1.1 ± 0.3

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 60 of 100

about the way in which lead would behave in a human being (Leggett, 1993). I think that her

statement about where the cesium goes in an animal is not untrue but it is misleading.

The question of how carcinogenic

137

Cs is not an easy matter to consider, but it is interesting

that she also states that

131

I is very carcinogenic. The problem is that Holm showed that moderate

(MBq) doses of

131

I does not induce thyroid cancer when it is used for thyroid examinations. If

Helen Caldicott considers

137

Cs and

131

I to be comparable in terms of carcinogenic strength then

on this scale

137

Cs is a very weak carcinogen. I then choose to look at the references in her book,

reference [45a] in chapter 3 is to a Suffolk County resolution which relates to an aggressive

malignant muscle cancer (In the references written as Rhabdo-myoma, I assume she means

rhabdomyoma). In the body of her book she wrote of rhabdomyosarcoma. A newspaper report

on subject of one of these resolutions stated it was the sarcoma (Tuma, 2000). Now I have to

confess that I dislike the excessive use of hyphens, but I hold the view that nothing would be

gained by nit picking on punctuation. But lets consider something more important.

She claims that exposure to radioactive cesium could cause this form of cancer. I hold the view

that this is a poor statement, one could argue that in theory that all forms of cancer could be

induced by anything which damages DNA. This is because radiation alters DNA, cancer cells

contain DNA which is different to that of the healthy cells from which the cancer evolved. But

we need to ask the question of “is radiation a common cause of rhabdomyoma or rhabdomyo-

sarcoma?”. I made a web of science search and found no link between “rhabdomyoma and

radiation”. One of the two papers which has both words simply mentions radiation as a treatment

for cardiac tumours and also states in the abstract that rhabdomyoma is a benign disease

(Gowdamarajan & Michler, 2000). On the other hand rhabdomyosarcoma is a different disease

to rhabdomyoma which can be induced in mice by irradiation with beta particles (Gupta, Andrews,

McDaniel Nagle and Bowden, 1999), and it has been observed in radiotherapy patients years after

treatment for an earlier cancer. But these two diseases are different conditions, I would be much

happier if Helen was to use a reference to the study of a cancer in the peer reviewed literature or

an easily available report from a national radiological protection organization rather than a local

law. I have looked at the resolutions and they are not scientific documents or statements of what

does (or what is thought to) cause cancer. Both resolutions are merely statements that an enquiry

(Gaffney, 2000a) will be made into the incidence of a form of cancer in the county and some

details of how this will be done (Gaffney, 2000b). To my mind her book misrepresents the contents

of the two resolutions. A charitable view can be taken that she made an error in writing the book,

but I hold the view that it is easily avoided mistake.

She also makes the bold statement that inhalation of a microgram of plutonium will result in

lung cancer. I will not deal with this statement here, I have commented on the risk of inhaling a

microgram of plutonium later in this review. Overall I think that many of the statements on

matters of science within chapter 3 of her book are either wrong or misleading. Also her choice

and use of references are not good. In general I would suggest that you the reader should be

careful with all information sources, even what I write. I would suggest that when you encounter

some idea or claim in the secondary literature that you should trace it back to the primary

literature. In this way form a judgement about the source in the secondary literature based on

facts rather than emotions. Now suitably warned we will start to look at some fission products.

4. Cesium

Cesium was released at Fukushima from the fuel, it then escaped from the plant. While much of

the cesium was either in the form of a water soluble compound or associated with organic matter

(Xu et al., 2015) some cesium in the form of water insoluble spheres was released (Adachi, Kajino,

Zaizen, & Igarashi, 2013). There spheres contain silicon and are likely to be some silicate spheres.

Radiometric measurements on seven of the most heavily internally contaminated TEPCO workers

indicate that inside their chests is an insoluble cesium compound (Nakano et al., 2016). This

observation can be explained by the inhalation of the cesium containing silicate spheres. It is

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 61 of 100

not clear yet how the presence of the insoluble cesium will alter the effective dose which the

workers receive as a result of inhalation of the radioactivity. This long-term retention of some

insoluble cesium in the lungs is not unique, both at Chernobyl and in an accident in Germany the

unusually long retention of cesium in humans was observed. In common with the long retention in

TEPCO workers this can be explained by the inhalation of insoluble cesium compounds.

Several independent reports exist of microscopic radioactive particles being emitted by

Fukushima, in some cases attempts have been made to chemically characterize these particles.

One very good study was conducted by Abe et al. (2014) in this study XRF and XANES were used to

detect the elements in the particles and to make an attempt at identifying the chemical environ-

ment of the elements. This study indicates that sodium, potassium, iron, zinc, rubidium, zirconium,

molybdenum, tin, antimony, tellurium, cesium and barium were found in the particles. In some

particles it was possible to detect magnesium, aluminium, lead, chlorine, calcium, chromium,

manganese and uranium. The XANES indicated that that iron, zinc, molybdenum and tin were

present in a soda-lime glass. This observation of a glass is consistent with the abnormally long

retention of the cesium in humans. In another paper (Kaltofen & Gundersen, 2017) it is claimed

that the microparticles contain tellurium (up to 48%), cesium (up to 15.6%), rubidium (up to

1.22%), polonium (up to 1.19%), dysprosium (up to 0.18%) together with radium, tin, lead, nickel,

iron and chromium all detected by scanning electron microscopy/energy dispersive X-ray spectro-

scopy (SEM/EDX). I have several criticisms of this work, firstly it is exceptionally difficult to be able

to measure with SEM/EDX a concentration of an element to three significant figures. Secondly I do

not believe the observation of the tellurium, polonium and radium by SEM/EDX.

The published X-ray spectra which the authors interpret as indicating the presence of a large

amount of tellurium, contains X-ray lines which are at the correct energy for the L lines of

tellurium. However the K lines of calcium are at very similar energies to the Te-L lines, I suspect

that the authors may have mistaken the calcium X-rays for tellurium X-rays. I do not believe that

sufficient radium would be present in the microparticles in an environmental sample for it to be

detectable by SEM/EDX. The authors stated that they had used gamma spectroscopy to examine

the samples. I reason that if the samples had contained a large amount of radium together with

radon then the radium (and its daughters) should be very noticeable by gamma spectroscopy. This

brings us to the problem of a person getting the “right”answer by the “wrong method”. I reason

that if a person using a totally inappropriate process in an attempt to obtain an answer or make a

choice, and by some miracle they arrive at the correct answer then while it was good that they

obtained the correct answer they may well lack the ability to consistently get it right. Thus their

work or method is not trustworthy.

Experiments on the leaves of trees indicate that the Fukushima cesium is mobile within a tree.

One problem with cesium is that multiple releases have occurred. For example nuclear bomb

detonations have released

137

Cs while Chernobyl released both

134

Cs and

137

Cs. The shorter half-

life of

134

Cs (2 years) means that the Chernobyl

134

Cs has almost totally decayed away by now.

Over 15 half-lives have passed since the Chernobyl accident, thus this cesium radionuclide has

decayed by a factor of more than 32,768. As

134

Cs is formed by neutron activation of stable

133

Cs it

can never observed in the fallout from a nuclear bomb, unless for some reason a bomb was to be

fitted with a jacket of a stable cesium compound. As a result the

134

Cs to

137

Cs ratio in the leaves

of the trees is an important clue to the origin of the cesium. The

134

Cs:

137

Cs ratio in the leaves

which were exposed to fallout was the same as the leaves which grew on the tree after the

accident (Xu et al., 2016).

Radioactive fallout can be either deposited under dry conditions or during rain, or other pre-

cipitation, under wet conditions. The transfer of radioactivity to fruit is often higher when the

radioactivity is deposited under dry conditions. It can be reasoned that rain will wash the radio-

activity off the surfaces of a tree and into the soil. In the early years after an accident the main

source of cesium which goes into the fruit is the cesium which was deposited directly onto the

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 62 of 100

trees and was then stored inside the trees. In the early years the adsorption of cesium via the roots

is not very important (Antonopoulos-Domis, Clouvas, & Gagianas, 1991).

The aggregated transfer factor (T

) is the activity of the fruit (Bq kg

−1

) for a given amount of

radioactivity deposited onto the land (Bq kg

−1

−2

). This equation is normally used for fruit growing

on the tree in the first year. The aggregated transfer factor is given by the following equation

(Renaud & Gonze, 2014). Where IF is the interception factor (area of foliage for a given area of

land), tis the current time, t

is the time of the accident, T

(t−t

) is the term containing the true

translocation factor while λis the physical decay constant (days

−1

) for the nuclide.

Tag ¼IFta Tfr tta

ðÞeλtta

ðÞ

This equation suggests that the transfer of radioactivity from the leaves (and other surfaces) of the

tree to the fruit is proportional to the time between the deposition and harvesting of the fruit. I

suspect that under extreme conditions that the following equation might be more correct. As a

plant with very slow growing fruit which is contaminated with a radionuclide which relocates very

quickly will come to an equilibrium in which the fruit will have a constant radioactivity (A

fruit

)ata

time after the deposition of radioactivity (A

land

AFruit ¼AlandIFta k01ektta

ðÞ



eλtta

ðÞ

It is important to understand that the transfer of radioactivity to the fruit in the first years after an

accident will not be the same as the degree of transfer to fruit from the same tree many years

later, nor will it be the same as that for a new fruit tree which is planted after the accident.

Antonopoulos-Domis, Clouvas, and Gagianas (1996) found that the radioactivity of fruit grown in

the 1990s on trees planted after the Chernobyl accident was both lower than that of fruit from

trees planted before the accident, and the

137

Cs level of the fruit on the trees planted after

Chernobyl declined more slowly. These authors found that the radioactivity of the fruit was well

described by the double exponential equation when twas greater than 1 year.

At¼Aeγ1tþbeγ2t

In this equation Ais a constant for the cesium deposited directly onto the tree while γ

is a

constant (years

−1

), Bis the constant for the cesium adsorbed through the roots of the tree and γ

another constant. Finally tis the time in years. It is clear that in the years after an accident the

entry of the cesium (or most other radionuclides) will occur via the roots from the soil. For example

lemon trees growing in Brazil close to where a cesium accident occurred in the 1980s were found

to produce lemons with much lower radioactivity (83 Bq per kilo of dry mass) than the correspond-

ing activity of the soil (3,659 Bq kg

−1

) (Velasco et al., 2012). The soil to fruit transfer factor did

decrease as the fruit developed on the tree.

However in a greenhouse experiment on orange and olive trees it was found that the transfer

factors were higher. For an orange tree which had been growing on a

134

Cs contaminated calcar-

eous soil (pH of a 1:1 slurry 7.5, CEC 182 mmol kg

−1

, 6.8 mmol exchangeable potassium kg

−1

) the

transfer factor (for the edible part of an orange) increased from 0.7 in the first year, to 1.6 in the

second year and in the third year it was 2.8. This increase was surprising as in the vast majority of

studies I have seen the transfer of cesium to plants from soil decreases with time. When the

orange tree had been placed in an acidic light soil (pH of a 1:1 slurry 5.6, CEC 56 mmol kg

−1

2.2 mmol exchangeable potassium kg

−1

) the transfer factor was 90.6 in the third year (Skarlou,

Nobeli, Anoussis, Haidouti, & Papanicolaou, 1999). Again with the olive trees the transfer factor for

cesium from the soil to the fruit increased with time, and the transfer factors observed with the

acidic soil were higher. This clearly illustrates that transfer factor will change when the soil or the

species of plant is changed. The increase in transfer factor was surprising as in the vast majority of

studies I have seen the transfer of cesium to plants from soil decreases with time. This is likely to

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 63 of 100

be due to the gradual increase in K

as the cesium becomes more strongly bonded to the soil

minerals (Sanzharova et al., 1994).

It is possible to change the soil by adding potassium to the soil. Currently on the Bikini Atoll

137

in food would be responsible for the majority of the dose which would be delivered if people were

to live on the island. The

137

Cs level of the trees on the island is decreasing faster than it would if

the only loss of the cesium was radioactive (physical) decay (Robison, Conrado, Bogen, & Stoker,

2003). But the

137

Cs level in the plants growing on the island is still high. One of the problems is

that the islands are made of a soil which was formed from coral, this is low in potassium.

It has been estimated that in 1999 an average person living on the island would get

0.42 mSv year

−1

from gamma photons from the

137m

Ba formed by the decay of

137

Cs outside

their body. If the island was cleaned up by removing soil from inside and around the houses the

external dose could be decreased. The soil would have to be replaced with crushed coral or some

other nonradioactive material. This would reduce the external dose from the cesium to

0.170 mSv year

−1

. For a person living on the island who is supplied with food imported onto the

island the internal dose would be 4 mSv year

−1

. This dose is mainly due to ingestion and very little

is due to inhalation of radioactivity. The 4 mSv year

−1

dose assumes no clean-up of the island. A

person living only on locally growth food would get four times as much exposure to internal

cesium (Robison et al., 2009). The

Sr,

239+240

Pu and

241

Am only make a small contribution to the

effective dose which people living on the island for 30 years would get regardless of whether they

ate imported food or locally grown food. If the soil removal work was done and the soil of the

island was treated with potassium then the sum of the external and internal dose received by a

person living on the island for 30 years would be reduced in either food scenario by a factor of

about 10.

Sadly potassium treatment of soil is not a panacea for cesium contaminated land. The applica-

tion of potassium has been shown to reduce the incorporation of

137

Cs into coconuts (Robison

et al., 2009), and the plants which sheep eat (Jones, Paul, & Mitchell, 1999). But the application of

potassium to land with low potassium soil can alter the plants. In a study on the reestablishment

of plants after a severe moorland fire it was found that potassium fertilizer alters the root/shoot

ratio of Calluna-Vulgaris (Legg, Maltby, & Proctor, 1992). I can imagine that the application of a

potassium fertilizer to a low potassium soil could alter the land by allowing plants which were

unable to thrive due to the lack of potassium to grow much faster.

Incineration offers a means of compacting waste and a method of recovering energy from

waste, after a radiological accident radioactive waste may be burnt either by design or inadver-

tently. A possibility exists that cesium will migrate through incinerator or power station ash. If

waste or biomass from a contaminated area is used as a fuel then radioactive cesium can appear

in the ash. Sadly it is impossible to give an easy answer as to what will happen, what happens

depends on the waste/fuel and the form of the cesium when it enters the plant. When tree bark

(either from deciduous or evergreen trees) was burnt the mass was reduced by a factor of circa 20

(Parajuli et al., 2013). The fly ash formed in this incineration when exposed to water released the

majority of the radioactive cesium with great ease. Likewise when contaminated municipal solid

waste (MSW) was burnt the fly ash formed when treated with water released its radiocesium with

great ease. In contrast when sewage sludge was burnt in a fluidized bed furnace the fly ash

retained its cesium when it was treated with water. Even treatment with nitric acid (0.5 M) with a

liquid to solid ratio of 100:1 for 1 h at 50°C only released 14% of the radiocesium. These results

with wood ash, MSW ash and sewage sludge ash strongly suggest either the fluidized bed

combustor or the sewage sludge itself creates an ash which does not release cesium with ease.

Parajuli et al. pointed out that the sewage sludge contained sand and soil, this might explain why

the cesium behaviour was different. If the cesium had been given time to exchange with other

cations in fine particles of clays then it would be in a non-water leachable form when it entered the

incinerator. It is a pity that the authors did not use the same furnace type for all the wastes which

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 64 of 100

they studied. The chemical form of the cesium in the ashes from MSW and sewage sludge were

examined with XANES. It was found that 80% the cesium in MSW fly ash was in the form of cesium

chloride while the remaining 20% was in the form of a cesium exchanged zeolite (pollucite). Two

samples of fly ash from sewage sludge were examined, in one all the cesium was in the zeolite

while in the other 90% of the cesium was in the zeolite and the rest was in the form of cesium

carbonate (Cs

) (Shiota, Takaoka, Fujimori, Oshita, & Terada, 2015). These XANES results

support the hypothesis of Parajuli et al. that the clay did alter the cesium leaching of the ash.

When radiocesium contaminated MSW was burnt in a stoker furnace 40% of the radioactive

cesium was routed into the bottom ash while the remainder was found in the fly ash. However

when decontamination waste, partly composted vegetable matter and soil, was burnt the majority

of the radioactive cesium was found in the fly ash. In this paper it was also found that the ashes

from MSW and the decontamination waste were different. The results of X-ray fluorescence

analysis indicated that the decontamination waste contained plenty of silicon and aluminium

but contained very little chlorine. The MSW contained much more chlorine and calcium (Nomura,

Maeseto, & Osako, 2017).

It was also found that it was much easier to leach cesium from the fly and bottom ashes formed

from the MSW than those from burning the decontamination waste. The authors concluded that

this was due to the fact that the very low chlorine content of the decontamination waste prevents

the formation of cesium chloride. The cesium chloride evaporates in the heat of the furnace before

condensing in the fly ash. From this work we can draw the conclusion that it is best not to burn

decontamination waste with a low chlorine content together with MSW. Even if a dedicated

incinerator for the decontamination waste is not available it would be better to burn the two

types of waste on different days at the incinerator.

5. Iodine

As I have commented on before during a reactor accident radioactive iodine can be released first

into the containment and then out of the plant. It is important that the amount of radioactive

iodine be measured. The reason is that without measurement it will be impossible to know if

protective measures such as sheltering, evacuation or changes in diet should be used to protect

the general public. Shortly after the Windscale fire in the UK the question of how to measure and

determine radioactive iodine was considered. During the Windscale fire emergency it is possible

that the iodine release was underestimated. Garland and Wakefield (2007) expressed the opinion

that during the underestimate may have been made of the amount of radioactive iodine which

was released. This was because the methods and devices used to collect the radioactive iodine

were not able to capture the organic iodines.

We need to consider how do we sample the different forms of radioactive iodine. Megaw and May

described two sampling devices which are filters, the simple one was two charcoal loaded filter papers

separated by an asbestos filter paper (Megaw & May, 1962). This combination of three layers is able to

capture iodine vapour andparticles. The secondsampler they described containeda millipore filter, two

charcoal impregnated filter papers and a pack (25 g) of activated charcoal. The Millipore filter was

shown to be able to capture radioactive particles, the charcoal papers were shown to capture ele-

mental iodine and finally the activated charcoal was shown to capture iodine compounds (Figure 23).

The more complex filter was referred to as the “May pack”by Chamberlain, Eggleton, Megaw,

and Morris (1963), a year later, the may pack was modified to include copper mesh disks to remove

elemental iodine from the air. These copper disks were placed in front of the Millipore filter. Now

with this improved design the device is able to distinguish between elemental iodine which is

captured in the copper gauzes, particles are still captured in the Millipore filter. In the 1970s it was

intended that a Maypack would be used to sample iodine in air in the event of a serious accident at

a nuclear power plant (Macdonald et al., 1977) (Figure 24).

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 65 of 100

The “May pack”was improved further in Japan, in 1988 the improved design of Noguchi and

Murata (1988) was used to study the iodine from the Chernobyl accident. The design was changed

two different versions were created. In one by adding a series of silver coated copper gauzes after

the Millipore filter any radioactive elemental iodine formed by the decomposition of particles on

the Millipore filter were prevented from reaching the charcoal impregnated filter papers. A second

charcoal pad was placed behind the first one to enable a check to be made that all of the organic

iodine was being captured in the first pad (Figure 25).

The second version of the filter by Noguchi et al. has a Millipore filter, five silver coated copper

gauzes, the two charcoal loaded filter papers and finally the two pads of activated charcoal. The

second version has the advantage that radioactive particles cannot be deposited onto the silver/

copper gauzes.

Using the Japanese version of the May-pack it was possible to determine that much of the

radioactive iodine (

131

I) which travelled from Chernobyl to Japan was in the form of organic iodine

compounds. The May-pack of Noguchi used charcoal which is impregnated with an amine, it is not

clear at what point these impregnated charcoals replaced simple charcoals. It is possible that even

the first Maypack used an impregnated charcoal but the details of the charcoal were not in the

early papers. A range of substances have been tested for their ability to enable charcoal to

intercept radioactive methyl iodide (Kitani, Noro, & Kohara, 1972). Without methyl iodide only

7% of the radioactivity was intercepted, while when DABCO was present 98% of the methyl iodide

radioactivity was retained.

Air Ai

Charcoal

Figure 23. The samplers used

by MeGaw and May. On the left

is the simple iodine vapour and

particles filter. The bold line is

the asbestos paper filter while

the two normal vertical lines

are the charcoal impregnated

paper filters. On the right is the

more complex device which can

provide more details of the

speciation of the iodine. The

dotted vertical line is the

Millipore filter (particles), the

two blue vertical lines are the

charcoal impregnated paper

filters (elemental iodine) while

the charcoal pad is used to

capture iodine compounds.

Charcoal

Figure 24. The improved “May

Pack”from 1963. The device

was improved by the addition

of the copper gauzes (dotted

red lines) which are in front of

the Millipore filter.

Charcoal

Figure 25. The first of the two

improved May-Pack devices

reported by Noguchi et al.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 66 of 100

While this is an interesting observation it is eclipsed by a German study on the speciation of

131

132

Te,

132

I and

133

I from Chernobyl over many days (Winkelmann et al., 1986). It is clear that the

particulate/elemental/organic ratios of

131

I and

133

I are similar. But the behaviour of the

132

appears to be different. With time for

131

I the organic iodine become more and more important

in West Germany after Chernobyl, the

133

I decayed away rather quickly but the

132

I which is the

daughter of

132

Te appeared to have behaved in a very different way. When the iodine (and

tellurium) was divided into three fractions (aerosol particles), elemental iodine and compounds

which absorb into a charcoal then the

132

I and

132

Te remained mostly in the aerosol fraction.

The most likely explanation is that

132

I was formed by the beta decay of

132

Te, but it was trapped in

the solid particles of the tellurium compound. The

131

I(t

= 8 days) is formed by the beta decay of

131

Te which has a half-life of 25 min, some 18% of the

131

I will be generated via

131m

Te which has a

half-life of 30 h. In contrast the

132

I(t

= 8 days) is generated by the beta decay of

132

Te which has a

half-life of 3.2 days. So while the

131

I emitted by Chernobyl was released as iodine (in whatever form)

the

132

I in Germany was delivered there as the precursor nuclide.

In a 1973 study on the release of

131

I from neutron irradiated tellurium it was shown that

tellurium oxides and telluric acid (Te(OH)

) need to be heated to over 400°C to release the radio-

active iodine (Shikata & Amano, 1973). The telluric acid decomposes in a series of reactions.

Te OHðÞ

6!TeO2OHðÞ

2!TeO3!Te5O11 !TeO2

It is clear that the tellurium compounds emitted by the Chernobyl accident when they were in

Germany were far too cold to release the

132

I within them. I suspect that some of the

132

I being

measured in during the counting of the sample will have been generated after the sample had

been taken. But the division of

132

Te and

132

I between the three fractions in the German study was

slightly different. This suggests to me that some iodine was able to diffuse out of the tellurium

containing particles or was otherwise separated from the tellurium.

6. Noble gases

Of all the fission products the noble gases are the most mobile, of all the reactor accidents which I

am aware of the most gentle are a subset of criticality accidents. It is a sad fact that in terms of

the number of deaths per joule of energy released by fission or the amount of radioactivity

involved they are unusually deadly. I will not discuss the entire litany of woes associated with

the 51 criticality accidents which I am aware of. But I will consider some issues associated with the

1999 accident in Japan as it include some interesting chemistry. Criticality accidents can be divided

in several ways, one classification is “Process Accidents”vs “Reactor and Critical Experiment

Accidents”. In a process accident there is never an intention to have a self-sustaining nuclear

fission reactor while in some of the reactor and critical experiment accidents there was an

intention to have some nuclear fissions. But during the accident far more fissions occurred than

were intended thus resulting in the accident occurring.

I hold the view that a fine line exists between a criticality accident and a reactivity initiated accident.

For example, SL1 accident, the Chernobyl accident and the 1954 explosion in the Borax reactor were all

caused by an excessive nuclear fission rate in the reactors. In all three cases the reactors quickly self-

terminated the nuclear reaction, steam explosions typically changedthe geometry of the reactors. The

January 1958 accident at Mayak was a deeply sad event, in common with the Chernobyl accident it

was an experiment intended to improve safety which went horribly wrong. But we will be considering

the Japanese accident in 1999. In common with the Mayak accident in early 1958 the Japanese

workers decided to alter a safe system of work to make the work more convenient. In both cases

people paid the ultimate price for the shortcut. But back to the chemistry.

Now as I have stated before the more volatile a fission product the greater the fraction released

from an accident. If we look at the fission products observed in the air after the 1999 accident in

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 67 of 100

Japan we find some rare radionuclides. We find

Sr,

131

133

135

138

Cs,

140

Ba and

140

La in air

samples (Inada, 2000). While the release of the iodine from a solution of uranium in nitric acid is

not a great surprise the release of the strontium, cesium, barium and lanthanum might be more

unexpected. I hold the view that no strontium, cesium, barium or lanthanum was released from

the uranyl nitrate solution, instead the noble gases

Kr (t

= 8.6 s),

138

Xe (t

= 14 min),

140

= 14 s) were emitted from the aqueous uranyl nitrate solution. The decay products (

Rb,

Sr,

138

Cs,

140

Ba,

140

La) of these noble gases would have deposited onto dust particles to form radio-

active aerosols. I am sure that some

135

Cs,

Sr and

Sr would have been released by the same

mechanism in the form of aerosols but the activity in terms of Bq or Bq m

−3

would have been much

lower for these cesium and strontium nuclides as their half-lives are longer. Also

Sr and

Sr are

pure beta emitters, to measure low levels of these a chemical separation from the other elements

in the collected sample is needed. While the event in Japan was a prolonged criticality lets

consider for a moment a single pulse of fission activity. We can use the Bateman equations to

deal with this problem.

If we consider the decay chain

Kr–

Rb–

Sr–

Y then if we were to have a fission event in

which 235 g of

235

U undergoes fission as a result of bombardment with thermal neutrons in a tank

of water in which noble gases are lost by a first order process into the headspace (half-life in tank

of 60 s). Then the number of atoms in the air above the liquid (headspace) can be predicted, we

assume that the aerosols do not return into the liquid (Figure 26).

It can be seen that the majority of the

Kr atoms become

Sr atoms in the aerosol, but

Sr has

quite a long half-life (50 days) so the radioactivity of the

Sr in the aerosol will not be high. While

some of my readers might be thinking 3.3 PBq is rather high, I can promise you that we will

consider a higher activity for a strontium soon. As can be seen in the following graph in which the

radioactivity of the different nuclides are shown (Figure 27).

If we repeat the calculations for the decay chain

Kr-

Rb-

Sr then at 10,000 s we have a much

higher radioactivity for the strontium in the air (46.3 PBq). The graph can be seen in Figure 28.

This is despite the fact that a far smaller fraction of the

Kr atoms end up as

Sr atoms in the

aerosol. Below the numbers of the atoms at different times can be seen in a graph of Figure 29.

If we consider a longer lived strontium product in the

Kr-

Rb-

Sr decay chain then we can

see that more of the strontium is found in the aerosol. But the final radioactivity of the strontium in

the aerosol will be much lower at “only”9.49 TBq. If the reader wants to read more about such

events then I suggest that they read the review by McLaughlin et al. (2000).

5E+21

1E+22

1,5E+22

2E+22

2,5E+22

3E+22

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Number of atoms

time post fission (s)

Number of atoms

Kr-89 in liquid Kr-89 total Kr-89 in headspace

Rb-89 in heads

ace Sr-89 in heads

ace

Figure 26. Prediction of the

number of atoms of different

nuclides with a mass of 89 in

both the liquid and the head-

space above a liquid.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 68 of 100

7. Tellurium

During both the Chernobyl and Fukushima accidents radioactive tellurium was released. Tellurium

is an element of concern as one of its isotopes (

132

Te) decays into a radioactive iodine (

132

I). When

both uranium dioxide (UO

) and a mixture of uranium dioxide and graphite are heated in oxygen

free helium after having been neutron irradiated then the

131

I is released at about 500°C while the

132

Te is released at 1,000°C. When oxygen (10

−5

atm.) is present in the gas then part of the

tellurium is released at 550°C while the majority is released at 1,000°C. When the oxygen level is

1000

100000

10000000

1E+09

1E+11

1E+13

1E+15

1E+17

1E+19

1E+21

1 10 100 1000 10000

Activity (Bq)

Time after fission

Kr-91 in liquid Kr-91 in air Rb-91 in aerosol Sr-91 in aerosol

Figure 28. Prediction of the

radioactivity of different

nuclides with a mass of 91 in

both the liquid and the head-

space above a liquid.

5E+21

1E+22

1,5E+22

2E+22

2,5E+22

0 1000 2000 3000 4000 5000 6000 7000

Number of atoms

Time after fission (s)

Number of atoms

Kr-91 in liquid Kr-91 total Rb-91 in aerosol

Sr-91 in aerosol Series6

Figure 29. Prediction of the

number of atoms of different

nuclides with a mass of 91 in

both the liquid and the head-

space above a liquid.

1000

100000

10000000

1E+09

1E+11

1E+13

1E+15

1E+17

1E+19

1E+21

1 10 100 1000 10000

Radioactivity (Bq)

Time after fission

Radioactivity

Kr-89 in li

uid Kr-89 in air Rb-89 in aerosol Sr-89 in aerosol

Figure 27. Prediction of the

radioactivity associated with

different nuclides with a mass

of 89 in the liquid and the

headspace.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 69 of 100

much higher (10

−3

atm or 0.1%, v/v) the tellurium is released at 550°C. In separate experiments

with

132

TeO

and

132

Te metal in pure helium it was shown that the

132

I is released at 300°C, the

132

Te from tellurium dioxide was released at 550°C and the tellurium metal released at 1,000°C

(Shiba, Hanada, & Yajima, 1969). The results of this study suggest that under the oxidizing

conditions found at Chernobyl that tellurium will be released from fuel at a lower temperature

than under the more reducing conditions found during Fukushima.

The release of tellurium from used fuel depends on the oxygen concentration around the fuel pins.

When zircaloy-4 is heated to 900°C in 20% oxygen in argon no segregation of tin from the zirconium is

observed during the oxidation. But at higher temperatures (such as 1,300°C) tin separated from the

zirconium in the oxide layer. When a sealed zircaloy tube containing tellurium, on the inner surface as

, was subject to prolonged oxidation (1,200°C in 20% O

for 5 or 10 h) the remains of the tubes

contained ZrO

,ZrTe

and SnO

according to powder diffraction. While a deposit of tellurium

dioxide (TeO

) was found in a cold trap. When the zircaloy tube containing tellurium was subject to

a shorter oxidation (3 h 20 min) under the same conditions the oxide layer was found by SEM with

EDX to contain inclusions of tin with tellurium. It was reasoned that tin telluride (SnTe) was formed

during the oxidation process. These tin telluride particles can be oxidized if they are heated further to

form tin and tellurium dioxides according to the following equation:

SnTe þ2O2!SnO2þTeO2

When mixtures of zirconium powder (85 w/w%), tin powder (5 w/w%) and a zirconium telluride

(Zr

10 w/w%) were heated at 1,000°C in mixtures of steam and hydrogen tellurium and tin

telluride were found in the condensed solids while the solid remains contained zirconium dioxide

(sometimes with tin dioxide). In the experiments with small amounts of hydrogen the mixture of

solids emitted tellurium vapour while in those experiments in which larger amount of hydrogen

were present the hot mixture of solids emitted tin telluride vapour (DeBoer & Cordfunke, 1997).

When the conditions are oxidizing both the tin and the zirconium are oxidized and elemental

tellurium is released. As tellurium is more electronegative than tin and zirconium it is reasonable

that tin telluride can react with water according to the following reaction.

SnTe þ2H2O!SnO2þTe þ2H2

In another study with the same grade of zircalloy the formation of zirconium tellurides (ZrTe

) was

observed when the oxygen concentration was low. Here the zircalloy surface had a coating of

zirconium tellurides were seen, on top of the telluride surface was observed a layer of zirconium

oxide. By X-ray powder diffraction both ZrTe and ZrO

were observed on the surface. When the

oxygen concentration was higher the zirconium surface was covered only with a thin layer

zirconium oxide and the tellurium was present as a vapour. In this higher oxygen level experiment

alpha-zirconium and zirconium dioxide were observed by powder diffraction (Arima, Masuzumi,

Furuya, Idemisu, & Inagaki, 2002). It is important to note that tellurium has a high affinity for the

platinum group metals such as palladium which are found in used fuel. In a high burnup fuel

metallic particles containing palladium and ruthenium are commonly found. These particles are

known as epsilon particles, already the thermodynamics of the interaction of palladium and

tellurium has been considered (Gosse & Gueneau, 2011). It might be possible to improve nuclear

fuel by the addition of palladium, Kolarik and Renard (2005) have reviewed the potential uses of

the platinum group metals formed by nuclear fission. One suggestion they pointed out in the

review is to use palladium (as described in a patent) (Grubb, 1976) to prevent fission cadmium

embrittleing the zircaloy cladding. Very little cadmium is formed as a fission product from uranium,

but the cadmium has a very harmful effect on the properties of the zircaloy (Shann & Olander,

1983). Shann and Olander also pointed out that iodine, iron iodide and aluminium iodide also

increase the rate of stress corrosion cracking (SCC) of zircaloy but cesium iodide does not have a

harmful effect. SCC is a corrosion process which occurs when a metal is subject to both tension and

a chemical attack which causes the surface to become brittle. What happens is that the surface of

the metal becomes covered with a brittle layer of a corrosion product such as metal oxide, a small

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 70 of 100

crack in the surface then locally increases the stress. The corrosion product cracks at this point and

when the crack reaches the ductile metal surface it stops growing. Then the chemical reaction of

the corrosion converted the newly exposed metal surface into a brittle substance, then the crack

can grow again thus exposing the metal surface again. This process can continue until the metal

object fails. A nuclear fuel pin inside an element will be subject to tension due to the internal

pressure, this can then lead to SCC.

While we can accept that cadmium metal is harmful to zircaloy cladding we need to ask

ourselves the question of why is cadmium so harmful. The first reason is that cadmium is volatile,

it has a boiling point of only 770°C. In a typical oxide nuclear fuel much of the uranium dioxide will

be much hotter than this. As a result the fission cadmium can be driven out of the fuel pellets and

into the gap between the pellets and the cladding. Secondly the cadmium is a very noble metal

compared with many of the others present in spent fuel as can be seen in the Ellingham diagram

(Figure 16) in the paper by Cubicciotti and Sanecki (1978). Thirdly exposure to cadmium together

with mechanical stress can cause SCC (Cahn, 1977). The palladium is likely to act by forming an

alloy with the cadmium and thus lowering the vapour pressure of the cadmium, this is concep-

tually similar to the use of zinc dust to make mercury spills less dangerous. If a wooden floor with

cracks becomes contaminated with mercury, one treatment method to remediate the room is to

rub zinc dust into the cracks in the floor. The zinc will then form zinc amalgam which has a lower

vapour pressure than pure mercury.

Additionally palladium has a high affinity for tellurium, if a combination of tellurium and palladium

powders are heated in a quartz tube it is relatively easy to form palladium tellurides (PdTe and PdTe

)

(Meijer, 1955). In addition to altering the cadmium and tellurium behaviour the addition of palladium

powder to fuel might be able to increase the thermal conductivity of the fuel. One enduring problem is

that uranium dioxide has a very low thermal conductivity, one solution I once encountered was the

idea of blending beryllium oxide (beryllia) into fuel (Ishimoto, Hirai,Ito, & Korei, 1996). I think that this

is a bad idea as it would increase the chemical toxicity of fuel production and also the used fuel would

emit more neutrons. A combination of an alpha emitter and beryllium generates neutrons.

Several methods exist for the separation of palladium from used nuclear fuel, recently it was

suggested that a BTBP dissolved in chloroform could be used to extract palladium from nitric acid

(2 M) (Zhang, Xu, & Lei, 2016). Zhang et al. used thiourea to strip the palladium from the organic

phase, this is thermodynamically similar to the work by Emma Aneheim, myself and Christian

Ekberg in which we used a different sulphur reagent (BIMET) to prevent the extraction of palladium

from nitrate media by a BTBP dissolved in cyclohexanone (Aneheim, Ekberg, & Foreman, 2012).

Having been involved with the development of BTBP as a solvent extraction reagent I am happy to

see further work being done on BTBP, but I strongly believe that a solution of a BTBP in chloroform

is not a suitable organic phase for the industrial scale extraction of palladium from either a fuel

dissolution liquor or a PUREX first cycle raffinate. This is for several reasons.

Firstly chlorinated solvents when exposed to ionizing radiation they tend to form chloride

anions, chloride contaminated nitric acid is very corrosive to SS316 which is the grade of

stainless steel which much of a reprocessing plant is typically made from. Secondly chloroform

istoovolatileforuseinalargescaleindustrialmetalextractionprocessIwouldbemorehappyif

they had developed chemistry using aliphatic kerosene or octanol. Lastly a cheaper extraction

agent exists, both in Russia (Torgov et al., 1994; Torgov, Tatatchuk, Druzhinina, Korda, & Renard,

2000) and Japan (Baba, Eguchi, & Inoue, 1986) the solvent extraction of palladium using simple

cheap dialkyl sulphides has been developed. The Russian process using poor quality (high

sulphur) diesel fuel does appeal to me as the organic phase is particularly cheap. Other ideas

for the separation of palladium separation which are based on BTBP (Zou, Liu, Ning, Wang, & Wei,

2017)orBTP(Liuetal.,2017) on silica have been suggested but again I think that it will be

difficult to devise a process based on silica which is better than the Russian solvent extraction

system.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 71 of 100

An alternative method of avoiding the dire effect of cadmium on the zircalloy would be to use

some other cladding, a range of alternative materials (fuel and cladding) have been considered for

use in more accident tolerant fuel (Zinkle, Terrani, Gehin, Ott, & Snead, 2014). I will not attempt to

discuss all of these suggests in turn but it is noteworthy that silicon carbide has been considered as

an alternative to zircalloy (Kim, Kim, & Park, 2013). Silicon carbide has already been used in pebble

bed reactor fuel, in the pebbles each contain a large number of small spheres of fuel which have

several layers of coating including one of silicon carbide. The diffusion of both iodine and silver

through silicon carbide has been studied. At 1,100°C very little diffusion occurred (diffusion

coefficients below 10

−21

−1

) but at higher temperatures diffusion of these elements was

observed (Friedland et al., 2011). One of the reasons for replacing zirconium cladding in nuclear

reactors is to design out of the reactor two chemical reactions. The first is the zirconium cladding/

fuel interaction which can generate additional heat during an accident but lower the melting point

of the uranium fuel.

Zr þUO2!UþZrO2;ðΔHro¼12:5 kJ mol1Þ

The second reaction is the zirconium/steam reaction which can generate both heat and hydro-

gen gas.

Zr þ2H2O!ZrO2þ2H2;ðΔHro¼525:8 kJ mol1Þ

For silicon carbide it is possible to react it with hot (1,000–1,300°C) steam according to the

following reaction (Cheng & Tortorelli, 2013).

SiC þ3H2O!SiO2þCO þ3H2;!ðΔHro¼92:2 kJ mol1Þ

We can calculate the relative heat yield for zirconium and silicon carbide using Hess’s law.

According to Chase (1998) and Cox, Wagman, and Medvedev (1984) at 25°C and 1 atm the heats

of formation of the important substances are listed in Table 18.

It is clear that the oxidation of silicon carbide will release far less heat per mole than that of

zirconium. The density of silicon carbide is 3.16 while that of zirconium is 6.52. Thus one litre of

silicon carbide is 78.8 mol of silicon carbide while one litre of zirconium is 71.5 mol. Thus if the

zirconium in the cladding in the reactor was replaced with the same volume of silicon carbide then

during an accident far less heat would be generated by chemical reactions in the core. We can also

calculate the heats of the following reactions:

UO2þSiC !SiO2þCþU;ðΔHro¼245:9 kJ mol1Þ

3UO2þ2SiC !2SiO2þ2CO þ3U;ðΔHro¼1284 kJ mol1Þ

It appears with the silicon carbide cladding that fuel cladding interactions like those of uranium

dioxide and zircalloy would not occur during an accident. The formation of carbon monoxide is

something which needs to be considered for at least two reasons. Firstly in modern water cooled

Table 18. Heats of formation.

Substance DH

° (kJ mol

−1

) Source

Water −285.83 Chase

Hydrogen 0

Silicon carbide (SiC) −71.55 Chase

Carbon monoxide −110.53 Chase

Silica −910.7 Cox et al.

Zirconium dioxide −1,097.46 Chase

Uranium dioxide −1,085.0 Cox et al.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 72 of 100

reactors it is normal to include hydrogen recombiners, one common type is the catalytic type using

finely divided platinum group metals to cause a flameless combustion of the hydrogen to form

water. The carbon monoxide could poison the surface of the catalysts. It is well known that the

platinum electrodes used in fuel cells for the oxidation of hydrogen gas are poisoned by carbon

monoxide (Jambunathan, Shah, Hudson, & Hillier, 2001). While carbon monoxide was found to

inhibit the oxidation of hydrogen by oxygen on the surface of a palladium/platinum alloy dispersed

on either stainless steel (SS316) or the silicate mineral cordierite, it was found that the poisoning

by carbon monoxide was not total. The catalyst using the cordierite was still able to oxidize

hydrogen when the carbon monoxide concentration was 1,000 ppm (Sanap, Varma, Waghmode,

& Bharadwaj, 2015). As a small amount of carbon monoxide is unable to strongly inhibit the

removal of hydrogen from the air in a reactor building using passive recombiners I do not think

that a core loaded with a mixture of zircalloy and silicon carbide clad fuel is more likely during an

accident to lead to hydrogen explosions like those seen at Fukushima than a reactor loaded only

with zircalloy clad fuel. I would like to point out that the Fukushima plants were not equipped with

passive recombiners, if they had been present in the reactor hall then the hydrogen-air explosions

are unlikely to have occurred.

Secondly if elemental iodine is released into an oxygen containing environment then the

radiolysis of the mixture would generate iodine oxide aerosols. This conversion of elemental iodine

into areosols could reduce the amount of iodine which escapes from a damaged plant. However if

carbon monoxide is released into the containment and reactor building of a stricken plant then it

could well reverse the radiolytic oxidation of iodine into iodine oxides. It is well known that iodine

(V) oxide reacts with carbon monoxide to form elemental iodine (Adams & Simmons, 1951).

But back to tellurium chemistry, once the tellurium escapes from the fuel in the reactor and

leaves into the containment. It was suggested that the tellurium could form hydrogen telluride

(Beahm, 1987). The heats of formation of the chalcogen hydrides decrease going down the oxygen

group. As hydrogen telluride is an endothermic substance with a heat of formation of 99.7 kJ mol

−1

(Chattopadhyay & Juneja, 1993) I hold the view that it will not be thermodynamically stable in the

containment. As the heats of formation of water vapour and tellurium vapour (Te

) and at 25°C are

−241.818 and 163.176 kJ mol

−1

it is possible to calculate the enthalpy of the following reaction to

be −519.9 kJ mol

−1

2H2TeðgÞþO2ðgÞ!2H2OðgÞþTe2ðgÞ

As the reaction below has the reaction enthalpy of −272.8 kJ mol

−1

I think it is reasonable to

assume that hydrogen telluride (or tellurided hydrogen) will react with the air to form tellurium

dioxide which will condense into solid tellurium dioxide.

Te2ðgÞþ2O2ðgÞ!2TeO2ðgÞ

The problem with thermodynamic instability is that countless examples of materials and systems

exist which are thermodynamically unstable relative to their decomposition products. For example

acetylene, picric acid and trinitrotoluene (TNT) both all decompose in exothermic reactions without

any oxidant present while cotton and other cellulose clothing in air is thermodynamically unstable

when compared with the combustion products. Plenty of soldiers walk around while carrying

explosive products (briquettes of TNT, and grenades filled with picric acid) while wearing clothing

made of cotton and other forms of cellulose without spontaneously exploding or bursting into

flames. While oxy-acetylene welding has been partly replaced by methods such as MIG (Metal In

Gas), I know civilian (and I assume military) motor mechanics often store acetylene in cylinders

normally without explosions or other misadventures. By the way acetylene cylinders normally

contain a solution of acetylene under moderate pressure in acetone dispersed on a porous solid.

Sadly while I have been unable to find papers on the mechanism and kinetics of the reaction of

hydrogen telluride with common oxidants such as ozone and nitrogen oxides, I have been able to

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 73 of 100

find papers on the subject of the reactions of hydrogen sulphide and hydrogen selenide with such

gases.

It has been reported that hydrogen sulphide reacts with the hydroxyl radical in the air to form

the HS∙radical according to the following reaction:

H2SþHO!HSþ H2O

The fate of the resulting HS∙radical has been considered by a computational study (Resende, 2007)

which suggested that nitrogen dioxide was the substance most likely in the air to react with this

sulphur centred radical. The reaction would be one of three reactions:

HSþNO2!HSOþNO

HSþNO2!SO þHNO

HSþNO2!NSOþHO

Of these Resende predicted that the first one forming HSO and NO would be the most favoured

reaction. Son et al. in their work on the destruction of sulphur compounds in air by electron beam

irradiation stated that the HSO radical reacts with ozone to form a series of new species (HO∙, SO,

HS∙, HSO

∙and O

). Through further reactions these form sulphur dioxide, sulphurous acid and

sulphuric acid (Son, Jung, Lee, Koutrakis, & Kim, 2015). It has also been shown that nitrogen

dioxide can react with the HSO radical to form the HSO

radical. The HSO

radical then reacts with

oxygen to form sulphur dioxide and the HOO∙radical according to the following equations (Lovejoy,

Wang, & Howard, 1987):

HSO þNO2!HSO2þNO

HSO2þO2!SO2þHOO:

I reason that if a mechanism exists for rapidly converting hydrogen sulphide to sulphur dioxide

with ozone and nitrogen oxides, then it is likely that hydrogen telluride is also likely to be converted

quickly into the oxide if it was to form in a reactor building. The reason why ozone and the nitrogen

oxides are important is that during a reactor accident a large amount of radioactive noble gases

are released into the containment. The action of these radionuclides on the air then generates air

radiolysis products which include ozone, nitrogen oxides and hydroxyl radicals.

A wide range of studies have been done on the chemical effect of radiation on air, for example

radon has been shown to generate HO∙and HO

∙radicals when humid air is exposed to the alpha

particles (Gfor the formation of HO

∙is 7.86 ± 0.13 radicals per 100 eV of energy) (Ding & Hopke,

1993). Also nitric acid formation has been observed in a proton accelerator facility used for particle

physics experiments in Japan (Kanda, Miura, & Nakajima, 2005). This nitric acid formation was

explained by Kanda et al. by reference to the work of Willis et al. here a series of reactions form

nitrogen oxides through a vast web of reactions which start with the N

formed by the ionization

of nitrogen molecules are considered (Willis, Boyd, & Young, 1970). These reactions include.

N2þþO2!N2þO2þ

N2þþe!2N

N2þþO2!O2þ2N

NþO2!NO þO

N2þO2þ!NOþþNO

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 74 of 100

The nitric oxide thus generated can then go onto form other nitrogen oxides and nitric acid if water

is present. The formation of nitric acid, nitrous acid and a series of nitrogen oxides in a high energy

electron—positron (antielectron) facility has been reported and a series of equations offered which

explain the changes in concentration of these air radiolysis products as a function of time (Kanda,

Momose, & Taira, 1996). These equations are likely to be of great use for considering the formation

of nitrogen oxides and nitrogen oxoacids in an air filled containment during an accident.

When oxygen is irradiated it has been shown that ozone is formed (Willis, Boyd, Young, &

Armstrong, 1970). Back to reactor accidents it has been argued that the air radiolysis products

can alter the iodine chemistry (Bosland, Funke, Girault, & Langrock, 2008). In Finland a large

amount of work has been done at VTT on this issue, for example Karkela et al. (2015) exposed

methyl iodide to beta particles in an oxygen containing environment. They found that the volatile

methyl iodide was converted into non-volatile iodine oxide particles. With a knowledge of the

results of the Finnish experiments it is reasonable to me that hydrogen telluride will be oxidized if it

is in air to which a large radiation dose is delivered.

8. Ruthenium

The releases of radioactivity from a reactor accident are largely controlled by the volatility of the

element and its simple compounds. However in the case of Chernobyl a large amount of ruthenium

was released. The NEA (Nuclear Energy Agency, part of the Organisation for Economic Cooperation

and Development [OECD]) report (Métivier & Waight, 2002) on page 35 in chapter 2 provides a table of

how much of each of a series of key radionuclides was released into the air. It is very interesting that

more than 3.5% of the

Mo,

103

Ru and

106

Ru in the core inventory was released. From the releases of

lanthanides and actinides it can be estimated that 3.5% of the fuel in the reactor was ejected into the

air. But the great question is why was more ruthenium than cerium/plutonium was released?

It is commonly accepted within the nuclear community that under oxidizing conditions that

ruthenium is released from fuel under oxidizing conditions. It is likely that the ruthenium forms

the volatile tetraoxide (RuO

) which then migrates within the nuclear power plant. Particles with very

large amounts of ruthenium were observed after Chernobyl which contained few other radionuclides

in large amounts (Sandalls, Segal, & Victorova, 1993). It is important to note that some ruthenium

hot particles have been examined years later and were found to contain

Co and

Ni (Kleszcz &

Mietelski, 2010), this suggests to me that these particles may have been formed from stainless steel

which was in or close to the core of the nuclear reactor. In addition to the

Co and

Ni the gamma

emitter

125

Sb has been observed in these hot particles (Broda, Mietelski, & Sieniawski, 1992).

Recently a PhD was defended at Chalmers on the subject of ruthenium chemistry under the

conditions of a serious nuclear accident. During this study it was found that ruthenium tetroxide

reacts with a range of surfaces (zinc, copper, aluminium and epoxy paint), using EXAFS it was

determined that the ruthenium on these surfaces was in the form of the dioxide (either tetragonal

or orthorhombic) (Kajan, Lasseson, Persson, & Ekberg, 2016). This observation of ruthenium dioxide

is not unreasonable as the tetroxide is a strong oxidant which is able to oxidize many organic

substances. Osmium tetroxide is well known as an oxidant which is able to convert alkenes into

1,2-diols. The ruthenium compound is a stronger oxidant which is able cleave alkenes. The

conversion of the tetroxide into the dioxide is in agreement with the hypothesis that ruthenium

vapour deposits onto existing particles and surfaces which are present during an accident.

However care should be taken with chemistry which is done using high concentrations of ruthe-

nium tetroxide, computational chemistry suggests that ruthenium tetroxide reacts with alkenes to

form a five membered heterocycle in a [3+2] cycloaddition (Frunzke, Loschen, & Frenking, 2004).

This then reacts with a second alkene in another cycloaddition to form a spiro compound. This is

then oxidsed by more ruthenium tetroxide to form a Ru(VII) compound which is able to decom-

pose into organic carbonyl compounds. This idea that after the initial reaction of the ruthenium

tetroxide with the surface that a reoxidation with more ruthenium tetroxide is required for some

oxidation reactions to occur suggests that the chemistry of ruthenium tetroxide with a surface

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 75 of 100

may be dependent on the amount of ruthenium present. It is important to note that the reaction

of ruthenium tetroxide with water to form ruthenium dioxide is catalysed by the surface of

ruthenium dioxide (McMurray, 1993). It is also important to note that not all surfaces have the

same ability to react with ruthenium tetroxide, it was found that metal oxide surfaces, borosilicate

glass and quartz are more reactive towards ruthenium tetroxide than clean metal surfaces

(Swider-Lyons, Love, & Rolison, 2005).

The oxidation of ruthenium or molybdenum metal in the presence of cesium iodide has been

reported to result in the formation of elemental iodine according to the following equation

(DiLemma, Colle, Benes, & Konings, 2015).

Ru þ2CsI þ2O2!Cs2RuO4þI2

It is interesting that if iodine has been deposited on a surface that it increases the absorption of

ruthenium, delivered as ruthenium tetroxide vapour, onto the surface (Kajan, Tietze, & Ekberg,

2016). Nitrogen oxides were found to increase the mobility of ruthenium as a vapour through an

air filled tube furnace, it was argued that nitrogen dioxide is able to oxidize species such as

ruthenium trioxide to ruthenium tetroxide (Kajan et al., 2017).

9. Silver

The origin of the silver in the Chernobyl fallout has been the subject of a lively debate in the letters pages

of Nature (Flowers, 1986; VanDam, 1986). In the fallout from both Chernobyl (Papastefanou,

Manolopoulou, & Charalambous, 1988) and Fukushima (Yu et al., 2015) some radioactive silver was

observed, two sources of radioactive silver exist in a nuclear reactor firstly it is a very minor fission

product. It is important to keep in mind that when uranium or plutonium undergoes fission thenucleus

splits into a small and a larger fragment. In terms of fission yield for these actinides a peak occurs

around zirconium/ruthenium and a second peak occurs in the early lanthanides. It is interesting to note

that as the energy of the nucleus which fissions is increased the fission becomes more and more

symmetric. Whenthe lower energy excited state of

236

U is replaced with the higher energy excited state

240

Pu the fission yield in the gap between the two peaks (around silver and cadmium) increases.

The second source of radioactive silver is as an activation product, silver is sometimes uses in

control rods and other equipment which is used inside nuclear reactors. Due to its very noble nature

silver is more likely to exist in the elemental form than cesium. However the boiling point of silver is

2,162°C which is much higher than that of cesium iodide (1,280°C). The boiling point of silver iodide is

1,506°C while this is higher than that of cesium iodide it is lower than that of elemental silver.

The radioactive silver from Fukushima along with

Sr,

110m

Ag,

134

Cs and

137

Cs (

Co and

below detection limits) was measured both in seawater and squid was measured by Yu et al. while

these radionuclides were detectable the level of these were too low to have a significant adverse

effect on the population of marine animals. Radioactive silver was also found in spiders (Nakanishi

et al., 2015), it was found that the spiders contained more radioactivity (Bq per kilo) than soil which

was surprising as silver is not considered to be an essential element for spiders.

While

110m

Ag was measured in the spiders the paper did not contain an assessment of the

possible health effects of a person being bitten by a radioactive spider. I hold the view that it is

unlikely that the radioactivity of a spider contaminated by Fukushima will contain sufficient

radioactivity to be of concern to a human. The most radioactive spider in the study contained

2,866, 11,464 and 17,445 Bq/kg of dry mass of

110m

Ag,

134

Cs and

137

Cs. The spider in question was

an Atypus karschi. So far I have been unable to find out the mass of this spider but I expect it

would be smaller than the Goliath Birdeater (Theraphosa blondi) which has a mass of 175 g. If we

were to be sufficiently unlucky that the spiders in Japan were to grow to the size of the alleged

birdeater from South America and to become aggressive to humans then we can calculate the

radiological consequences of a spider bite.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 76 of 100

A spider with a mass of 175 g and a specific activity of 17,445 Bq per kilo of dry mass would

contain 3,053 Bq of

110m

Ag if we assumed that the dry mass was the same as the mass of the

living spider. This I imagine is clearly impossible as a totally dehydrated spider would be unable to

live. Now if the spider was to bite some unlucky person and to be able to inject all its inventory of

radioactive silver into that person then using the ICRP 119 dose coefficients (Eckerman, Harrison,

Menzel, & Clement, 2012) then the dose to the unlucky person will be 0.171 mSv. This is a small

dose. I worked it out by assuming that an injection (spider bite) would be a 20 times higher a dose

per Bq as the f

value for silver listed was 0.05. As the dose to the unlucky person who was to be

bitten by a spider is far below 1 mSv then I think we do not need to worry about

110m

Ag containing

spiders biting either workers or members of the public. I also considered a person who eats a

“spider burger”, if we assume that a spider burger contains 250 g of spider meat which will contain

4,361 Bq of

110m

Ag, then each spider burger will result in a person getting a 12.2 µSv dose. Thus a

member of the public could eat 82 spider burgers made using the most radioactive spiders

mentioned in the paper per year before they would reach an additional dose of 1 mSv in 1 year

as a result of the consumption of this rather bizarre food.

While the fission products are normally discussed in this review in the context of the threat which

they pose, we should consider how some fission products have a beneficial effect. In high burnup fuel

research has suggested that palladium and silver could be able to sequester iodine under accident

and repository conditions (Buck, Mausolf, McNamara, Soderquist, & Schwantes, 2016).

10. Strontium

In the immediate aftermath of a nuclear accident such as Fukushima the gamma emitting radio-

nuclides such as

131

132

Te,

132

134

Cs,

137

Cs,

140

Ba and

140

La can be measured by means of gamma

spectroscopy. While the measurement of gamma emitters is not a trivial matter it is possible to

make the measurement without doing any radiochemistry or much of another form of sample

preparation. On the other hand the analysis of the pure beta strontium radionuclides is rather

more complicated. As a gamma photon is emitted by a nucleus it is a two body system, as the

energy of the excited state is well defined, and the energy of the state the nucleus is relaxing into is

also well defined the gamma photons for a given transition are monenergistic. However when a beta

decay (electron emission) occurs the energy is shared between the daughter nucleus, the electron

and the neutrino. As the angle between path of the electron and the neutrino is variable the relative

share of the energy taken away by the electron is not well defined. Beta decay spectra tend to be

broad smears instead of the sharp peaks seen in alpha and gamma spectra. Even if the radioactive

decay occurs within a detector which would be able to sense the sum of the energy of the recoiling

daughter atom and the electron the fact that the amount of energy taken away by the neutrino

varies will make the beta spectrum a board peak rather than a sharp set of lines.

It is often important to separate the strontium from the other elements in an environmental

sample before the strontium is measured. For example soil can be digested in acid before the

solution of the strontium (and other elements) in nitric acid (8 M) is applied to a polymer resin

bearing 40% (w/w) of a 1 M solution of 4,4ʹ(5ʹ)-di-t-butylcyclohexano 18-crown-6 (crown ether) in

octanol. The resin column was first washed with nitric acid (8 M), nitric acid (3 M) with oxalic acid

(50 mM) and finally the strontium was eluted with dilute (50 mM) nitric acid. The resulting

strontium solution was measured by means of liquid scintillation counting (LSC) (Sahoo et al.,

2016). The separation of the strontium using such a resin (Horwitz, Dietz, & Fisher, 1991), the

chemistry of the separation is very similar to that of the SREX solvent extraction process for the

removal of strontium from liquid radioactive waste (Wood & Law, 1997). While the resin is able to

reject calcium, sodium and cesium it has a very high K

value for lead. Thus any

137

Cs will be eluted

quickly through the column while any

210

Pb in the sample will be retained by the resin. When the

nitric acid concentration is 1 M the K

value of polonium(IV) is about 100, when the nitric acid

concentration is 10 M the K

for polonium is about 1. Thus much of the

210

Po in the sample will

never adsorb onto the column, that which is absorbed is likely to be washed out by the nitric acid

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 77 of 100

(8 M) washing (Horwitz, Chiarizia, & Dietz, 1992). Thus with this resin it is possible to separate the

strontium from many of the radionuclides which could interfere with the final LSC measurement.

The methods of separation of strontium and the measurement of radioactive strontium have

been reviewed (Vajda & Kim, 2010). Much of this review is very good but I hold the view that the

statement that “Couple of years after a nuclear incident

Sr,

Y and

Y will be present

together in the environment”which appears in the review is misleading.

If we consider the case of Chernobyl, reactor 4 at the moment of the accident is thought to have

had an inventory of 2,300 PBq

Sr and 200 PBq

Sr, of which circa 5% was released. If were to

have assumed that the reactor had been running at a constant power before the accident then it is

quite easy to calculate the activity of

Sr which would have been present. To a first approximation

the number of atoms of a given activation or fission product (N

) are given by the following

equation while the fuel is in the pile. Where N

is the number of atoms of the target, R

is the

rate constant for the generation of the atoms of N

in the neutron field, λ

is the decay constant of

and tis the irradiation time.

N2¼ðN1R1Þ

λ21eλ2t



If we assume that only one fissile nuclide is present then the equation can be used, in real life a

reactor fuel contains both

235

Uand

239

Pu. Much of the energy released by the fuel in a reactor is due

to plutonium fission. If we assume that thermal neutrons are responsible for all fissions then the

equation can be kept simple. It can be calculated that the fuel would have been in the pile for about

1,100 days and it would have contained 2,787 PBq of

Sr and

Y at the moment of the accident.

We can add a term to our equation to consider the decay after an object comes out of a nuclear

reactor. Now we have two times, t

reactor

is the time in the reactor while t

cool

is the cooling time

after it comes out of the reactor.

N2¼ðN1R1Þ

λ21eλ2treactor



eλ2tcool



Assuming that at t

cool

= 0 we have 2,300 PBq

Sr, 200 PBq

Sr, 2,787 PBq

Sr and 2,787 PBq

then after 2 years (730 days) we would have 112 TBq

Sr, 190 PBq

Sr, no

Sr and 522 TBq

While the

Sr and

Y might be possible to measure, their effect on a measurement of

Sr after

2 years would be very small after a reactor accident with relatively old fuel such as Chernobyl. On

the other hand after an accident with a younger fuel (less time in the pile) such as submarine

accident at Chazhma Bay near to Vladivostok in August 1985 would have a

Sr:

Y ratio much

closer to that of an atomic bomb. Shortly after a reactivity spike in fresh fuel I would expect an

activity ratio of 166:1:174 for these radionuclides.

The alternatives to the use of the crown ether bearing resin include precipitation. One method is

to use nitric acid to form solid strontium nitrate while the calcium nitrate remains in solution

(Willard & Goodspeed, 1936). To my mind this method sounds rather disagreeable, it has the

potential to generate large amounts of acidic waste.

It is important to note that barium chromate and lead chromate both have much lower solubility

products than that of strontium chromate. This offers a means of removing any

140

Ba which might

be present in a sample of

Sr and

Sr from a reactor accident.

11. Actinides and lanthanides

Of all the elements plutonium provokes great public excitement and horror. It is interesting to note

that plutonium is poorly adsorbed when swallowed in food, water or mucus. For example when

humans in 1995 ate cockles from the Irish Sea which contained plutonium, americium, cobalt,

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 78 of 100

cesium and technetium (as a result of discharges from Sellafield) very little radioactivity was

incorporated into the people (Hunt, 1998). Measurements were made of faeces and urine to

determine what fraction of the radioactivity in the meal of cockles (375 g) was adsorbed by the

digestive system into the body. It was found that for plutonium on average only 0.34% of the

plutonium was adsorbed by the human digestive system. The highest f

value observed was

7×10

–4

which indicated for one person that 0.7% of the plutonium was adsorbed from the

digestive system. This study suggests that even soluble plutonium is poorly adsorbed by humans.

The measurements for americium were also reassuring, the average f

value was 5.4 × 10

–4

suggesting that only 0.54% of the americium swallowed was adsorbed.

However the f

values for

Co and

Tc were about 0.2 (20% adsorbed) and 0.6 (60% adsorbed)

suggesting that one cannot always eat radioactive cockles with total impunity. One interesting

observation in the study was that the transfer factor for

137

Cs was 0.21 thus indicating that the

adsorption of cesium from the digestive system is not total. The number of subjects in this

experiment was small and it is not clear what the chemical form of the cesium contamination

of the seafood was. If the cockles had contained small particles of clay minerals on which were

adsorbed cesium then this could well reduce the adsorption of the cesium into the body.

It is well known that many samples of plutonium are in the form of plutonium dioxide, I hold the

view that the f

values for plutonium dioxide will be lower than plutonium in seafood. As plutonium

dioxide is exceptionally insoluble, I reason that it will not dissolve in the stomach or in lung fluid.

Instead of being a threat when humans are exposed in their diet I reason that it is more able to

pose a threat when it is inhaled. The insoluble particles could remain in the lungs for some time

where they are then able to deliver a dose of alpha particles to the lung tissue. I reason that

injections of plutonium are exceptionally rare, I am aware of some ethically questionable human

experiments and some workplace accidents where different forms of plutonium have been

injected into humans.

We will concentrate on the threat posed by inhaled plutonium.

Greenpeace have made the following bold statement about it (Greenpeace, 2006).

“Inhalation of a single microgram of plutonium, smaller than a speck of dust, can cause fatal

lung cancer. There is no safe dose of exposure for humans, and once it is inside the body, it will

remain there for a very long time—longer than the average human life span.”

I will subject the statements in this paragraph of text to a detailed analysis, but before we go any

further it is interesting to consider the number of pages within the domain of the environmental

organization (www.Greenpeace.org) which mention plutonium compared with some other ele-

ments. A random list of elements

including plutonium was made, when a series of internet

searches were made for Greenpeace pages mentioning these elements a total of 103,684 pages

were found, the search for plutonium yielded 2,510 pages (2.4%) which is higher than the average

for the elements which was 2.0%. You might be interested to know that 30,600 pages (29.5%)

mentioning carbon were found in this search. While this experiment is far from perfect it does

indicate that some elements are mentioned more than others by Greenpeace and that the word

plutonium appears on more pages than if the mention of elements was totally random.

I have to ask the question of “can a single microgram of plutonium induce lung cancer”. I have

to conclude that the answer is yes but the statement is misleading. A single atom of plutonium

could in principle induce cancer if it was to undergo a radioactive decay when it was in the wrong

place at the wrong time. But this says nothing about the likelihood that a single microgram (or

single atom) will induce cancer.

Using recent dose coefficients from the ICRP (Eckerman et al., 2012) I calculated that 1 µg of

plutonium (

239

Pu) in the form of a powder of a substance (1 µm particles) which slowly transfers

into the blood (class S) will deliver an effective dose of 34 mSv to a person. If the material is in the

form of a substance which transfers into blood at a moderate rate (class M) then the committed

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 79 of 100

dose due to this 1 µg of plutonium will be 108 mSv. While these doses are not trivial, these doses

are far below the doses which would be required to have at least a 50% chance of inducing cancer.

I expect that if a person was to get a 108 mSv effective dose then they would have an addition

0.5% chance of developing cancer. As a result I think that the first statement while technically

being true is one which is misleading.

A great problem is that very few samples of plutonium only contain a single isotope of plutonium,

for example I saw a paper on a release of weapons grade plutonium (

238

Pu 0.0099% w/w,

239

93.7% w/w,

240

Pu 5.6% w/w,

241

Pu 0.47% w/w) (Lee & Clark, 2005). Then it can be calculated with the

same ICRP coefficients it can be seen that bomb grade plutonium is slightly more toxic than pure

239

Pu plutonium. The committed effective dose from the inhalation of class M bomb grade plutonium

in the form of 1 µm particles will be 141 mSv. Even while it is higher than the dose of 108 mSv it is not

a dose which has a high probability of causing cancer or a serious disease. I repeated the calcula-

tions with a reactor grade plutonium isotope signature (

238

Pu 2.947% w/w,

239

Pu 42.401% w/w,

240

Pu 33.562% w/w,

241

Pu 10.372% w/w and

242

Pu 10.715% w/w) (Serrano-Purroy et al., 2005). I

choose a very poor quality reactor grade plutonium which would be very unsuitable for building a

bomb, it is important to bear in mind that a range of plutonium isotope signatures can be found both

in “weapons grade”and “reactor grade”plutonium. The committed effective dose from 1 µg of this

plutonium in 1 µm particles of the M type is 1,318 mSv. While this is a much larger dose than can be

expected with a weapons grade plutonium it is important to note that this dose increases a person’s

lifetime risk of cancer by 6.6% which is a dose which I would strongly wish to avoid but it does not

make death by cancer a certainty. I note that much of the alpha activity in the reactor plutonium is

due to

238

Pu which has a relatively short half-life.

Helen Caldicott made an even more bold statement, she claimed that inhalation of less than a

single microgram of plutonium will induce lung cancer in her book (Caldicott, 2006). Sadly this

statement does not have a reference associated with it, and she makes some further claims about

plutonium and other elements. I find it interesting that during her public debate with George

Monbiot she told him on several occasions to read one of her books. The problem I see is that if her

books are poorly referenced and she has not generated any results through her own research thus

making her a poor source. For various reasons I am unable to repeat all the research mentioned in

this review, but I make a point of providing reliable references to support the ideas which are

presented in this review. I also would like to stress the importance of checking your references,

where possible I tend to read more than one paper on a subject and when I do calculations if I

obtain an unusual result I check my work with great care.

Helen continues to state that white blood cells translocate plutonium from the lungs. I am

aware that macrophages do engulf and attempt to digest foreign bodies and microbes, some

literature does exist on plutonium and macrophages. In the 1960s, it was shown by Sanders and

Adee (1968) in rats that macrophages present in the lungs do engulf and accumulate fine particles

of plutonium dioxide. So on the issue of white blood cells Helen is right, but I do so wish she would

reference her books better. It is interesting that chronic exposure to cigarette smoke reduces the

clearance of plutonium dioxide from the lungs of rats (Finch et al., 1998), which is consistent with

the observation that smoking harms the ability of the body to remove dirt from the lungs.

Helen also states that plutonium can migrate into the lymph nodes, this is true for example

recently it was shown using tissue from a former nuclear worker, who had been heavily exposed to

plutonium, by laser ablation inductively coupled plasma mass spectroscopy (LA-ICPMS) that

plutonium can be found in lymph nodes (Hare et al., 2010). Helen next states that plutonium

causes lymphoma or leukaemia. In the Mayak workers plutonium exposure is associated with lung,

liver and skeletal tumours but not with leukaemia (Shilnikova et al., 2003). In that population no

statistically significant link exists between plutonium exposure and either lymphoma or leukaemia

(Kuznetsova, Labutina, & Hunter, 2016).

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 80 of 100

She also makes the bold claim that plutonium is appearing in the testicles of men and then

harming the health of their offspring. Using urethane and X-rays Nomura did observe an excess of

tumours and abnormalities in mice as a result of preconception exposure of both male and female

mice (Nomura, 1982). Likewise with neutron irradiation it has been shown that the offspring of the

irradiated male mice have shorter lifespans (Russell, 1957). The male offspring of male mice

irradiated with fission neutrons from

252

Cf have a higher rate of liver cancer than the male control

mice (Takahashi, Watanabe, Dohi, & Ito, 1992). It is interesting to note that these neutrons are

more able to induce liver cancer in mice than

Co gamma rays.

But with plutonium different results were obtained, male mice who had been injected with

plutonium citrate (3 or 40 mGy testicle dose) after mating (8–10 weeks later) with female mice had

offspring who had no excess of leukaemia or other diseases (Selby & Priest, 2005). Some attempts

to repeat Nomura’s observation have failed to observe an excess of disease in the offspring, for

example when male mice were treated with 600 R of X-rays, these male mice went on to father

offspring which were no different to unirradiated mice (Cosgrove et al., 1993). When Cattanach

et al. (1995) investigated the incidence of lung cancer in the offspring of male mice irradiated with

0, 2.5 or 5.0 Gy of X-rays they failed to find evidence that the preconception irradiation harmed the

offspring. In one early US study by what I would describe as very patient workers, it was found that

neither 10 or 35 inbreed generations (brother/sister matings) in which all the males were irradiated

with 200 rads of X-rays caused a shortening of the lifetimes of the females when they were

compared with a control experiment using no irradiation (Spalding, Brooks, & Tietjen, 1969).

But in another study (Lord et al., 1998)itwasfoundthatmalemiceinjectedwith128Bqg

−1

239

(as the citrate) these male mice had offspring who were more sensitive to the induction of cancer when

they were exposed to N-methyl-N-nitrosourea. However male mice injected with 256 Bq g

−1

of pluto-

nium citrate had offspring who did not clearly show an increased sensitivity to the chemical carcinogen.

However with exposure to urethane Cattanach et al. (1998) were able to see little or no effect of

preconception irradiation of male mice on the incidence of lung tumours in their offspring (Table 19).

However with tritium (HTO) exposed male mice it has been found that an increase of the

leukaemia rate in their offspring does occur (Daher, Varin, Lamontagne, & Oth, 1998). Thus it

does appear that contradictory results on preconception irradiation exist in the literature. It is

interesting that a defect may exist in the transgenerational carcinogenesis experiments using

radiation, with a high dose of radiation which appears to result in unhealthy offspring the high

dose of radiation decreases fertility. Thus the litter of mice is smaller, the young mice have higher

body masses and a high body mass in mice is linked to an increased rate of cancer (Selby, Earhart,

& Raymer, 2005). As a result I would be very careful not to make a claim that plutonium is harming

human health by damaging the testicles of men.

In the case of the mice the internal exposure of their fathers to plutonium may have altered

their sperm in some way that their offspring were more susceptible to cancer. Sadly there are

Table 19. Details of rodent plutonium injection experiments.

239

Pu dose Time between

injection and

mating

Testicle dose

(mGy)

Later challenge

with a chemical

carcinogen

Outcome

654–68 3 No No harmful effect

60 54–68 40 No No harmful effect

128 84 118 Yes Increased susceptibility to

the chemical

carcinogen

256 84 235 Yes No harmful effect

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 81 of 100

people who have defective copies of some genes which predispose them to cancer, for example

the actress Angelina Jolie has a defective BRCA1 gene which causes her cells to be less able to

repair defective DNA. But I find it hard to imagine that the random DNA damage by the plutonium

would have a high probability of damaging a given gene. But we could imagine that if a series of n

changes are needed to the DNA of a cell to create a cancer cell that if a damaged sperm cell was

fused with an egg to form an embryo that the damaged sperm could pass on some damaged

dominate gene which promotes the formation of cancer. This would then appear in every cell of

the animal which is born, but these changes might only matter in some tissues. But overall it is not

clear that this works in mice and the birth number/weight effect might create some false positives.

I am aware of a person who lived for almost 40 years after being exposed to an aerosol of acidic

plutonium(IV) nitrate solution. This person at autopsy had 0.83 Bq of plutonium in his testicles,

while he had 937 Bq in his liver, 1,170 Bq in his skeleton (Total body burden of 2,317 Bq from an

intake of 58,000 Bq) (Nielsen et al., 2012). This suggests that very little of the water soluble

plutonium was deposited in his testicles.

The second statement by Greenpeace that “There is no safe dose of exposure for humans”is an

interesting statement. If we assume that the LNT model applies to the induction of serious

diseases by radiation then it can be easily argued that while any exposure to plutonium has the

potential to cause a harmful effect. Some very small exposures cause such a small harmful effect

that they should not be of concern to either a person or a regulatory body. I am unsure if it is

possible to die as a result of the acute effects of a large number of paper cuts but I can imagine

that it might in theory be possible to induce a serious disease by suffering a papercut while

handling some unpleasant substance. I have to ask if it is reasonable for the citizen, regulatory

bodies and industry to attempt to take steps to prevent some horrible but exceptionally unlikely

event. For example while either reading a printed copy of this article or a pamphlet from an

environmentalist a person might cut their hand and infect themselves with some unusually

harmful microbes which then cause some horrible outcome. I hold the view that some risks are

sufficiently small that they can be ignored.

The last statement is also interesting, the short paragraph includes the text “once it is inside the

body, it will remain there for a very long time—longer than the average human life span”. The first

problem is the question of “what is inside the body”. From an anatomical point of view the

contents of the digerstive system is outside the body as is the air which is inside the lungs.

However for many people after an item is swallowed or a substance inhaled it is regarded as

being inside the body. I sincerely wish that Greenpeace’s writer had been more clear on what is

“inside the body”. I know from cases in which people have been injected with plutonium that the

plutonium can remain inside a person for a very long time. For instance at Hanford in 1985 a man

accidently cut himself while working with plutonium, he injected himself with 48 kBq of alpha

activity (mainly

239/240

Pu and

241

Am) (Carbaugh, Lynch, Antonio, & Medina-Del Valle, 2010). By

means of surgery the long-term activity in the wound was reduced to 5.4 kBq, and using DTPA

(Diethylene Triamine Penta Acetic acid) it was possible to remove circa 7 kBq of alpha activity was

removed from the man but much of the alpha activity remained inside the man. Despite this

plutonium injection accident the man is healthy 24 years after the accident.

After an interesting trip down a rabbit hole of often repeated claims about plutonium toxicity we

can conclude that plutonium exposure is harmful to health and is most likely to affect the lungs,

liver and the skeleton. But back to reactor accidents, if a violent event occurs inside the core which

is able to eject fuel in the form of fine particles (as happened at Chernobyl) then it is possible for

appreciable amounts of plutonium to escape from a reactor. It has been estimated that circa 3%

of the plutonium in the core at Chernobyl was ejected from the plant. I hold the view that in the

event of a reactor accident it is likely that the curium (

242

Cm) release and the growth of americium

(

241

Am) could be just as important as the plutonium release. Using data from Finland (Salminen,

Paatero, Jaakkola, & Lehto, 2005) we can see the importance of the

242

Cm and the ingrowth of

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 82 of 100

241

Am in the following charts. In the first chart we can see the radiotoxicity of the transuranium

elements decreases in the first 3 years before increasing again (Figure 30).

The decrease in the first 3 years is due to the decay of the

242

Cm, the increase which occurs up to about

36 years is due to the formation of the alpha emitting

241

Am by the beta decay of the

241

Pu. The decrease

at the right hand side of the graph is due to the decay after 40 years is largely due to the decay of the

238

Pu and the

241

Am. The final transuranium radionuclides which will be leftin the distant future will be

239

Pu,

240

Pu and

242

Pu.

In the following graph we can see that for the much of the first 650 years the

241

Am is the most

important radionuclide, we can see it growth and then start to decay in Figure 31.

In Figure 32, I am showing the first decade to show how the curium decays away within the first

3 years.

While Chernobyl released about 3.5% of its plutonium, the Fukushima accident released far less

of the transuranium actinides. By examining a soil sample taken 300 km from the stricken plant it

was possible to find the more mobile fission products (

131

I 114 kBq m

−2, 132

I 9.74 kBq m

−2, 134

7.31 kBq m

−2, 136

Cs 0.976 kBq m

−2, 137

Cs 7.49 kBq m

−2, 132

Te 13.2 kBq m

−2, 129m

Te 6.10 kBq m

−2,

129

Te 9.62 kBq m

−2, 140

Ba 0.00749 kBq m

−2

and

140

La 2.83 kBq m

−2

) but it was not possible to find

either plutonium or americium in the sample by alpha spectroscopy (Zhang, Friese, & Ungar, 2013).

0,2

0,4

0,6

0,8

1,2

0,01 0,1 1 10 100 1000 10000

Relative toxicity

TIme (

ears)

Figure 30. The change in the

radiotoxicity of the transura-

nium actinides released by

Chernobyl.

100

0 500 1000 1500 2000

Contribution to radiotoxicity

Years

Pu Am Cm

Figure 31. The relative contri-

bution of plutonium, americium

and curium to the radiotoxicity

of transuranium elements

released by Chernobyl.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 83 of 100

The NEA report on Chernobyl estimated that circa 900 TBq of

242

Cm was released while only 35, 30

and 42 TBq of

238

Pu,

239

Pu and

240

Pu were released by the accident.

The tiny trace of transuranium radionuclides has been measured in Japan in some very careful

work (Yamamoto et al., 2014). When I repeat the calculations using data for unit 1, I saw that

242

Cm make a similar addition to the toxicity in the first years after the accident but there the

americium would be slightly less important. This is likely to be due to the fact that

238

Pu content in

the Chernobyl fuel was lower than it was at Fukushima. In Table 20, some of the atomic ratios in

the fuels at Chernobyl and Fukushima are shown.

Currently in the basements underneath unit 4 at Chernobyl the water contains a mixture of

Sr,

137

Cs,

234

238

Pu,

239+240

Pu,

241

Am and

244

Cm (Odintsov, Khan, Krasnov, Pazukhin, &

Shcherbin, 2009). According to Odintsov et al. the activity ratio of the transuranium elements is

different in the fuel and the water (Table 21).

It can be reasoned that the post-plutonium elements (Am and Cm) which normally form trivalent

cations are more able to dissolve out of the wreckage than the plutonium which tends to be in the

tetravalent state. This can be rationalized by the fact that the tetravalent plutonium will absorb more

strongly onto surfaces and its water complexes are more likely to undergo hydrolysis. While the

trivalent actinides are highly charged and will tend to absorb and precipitate these effects are

weaker than those for the tetravalent plutonium. But much of the alpha activity in the waste

water from the basement of unit 4 at the Chernobyl site is not in the form of free (or hydrated)

cations. While very little of the

137

Cs (beta/gamma) or the uranium is removed by filtration through a

0.01 µm (10 nm) filter, when the water is filtered through a 0.1 µm (100 nm) filter about half of the

plutonium is retained by the filter. On passing the filtrate from the 0.1 µm filter through the 0.01 µm

filter a little more plutonium is removed from the water. I think that the waste water from the site

can be freed of plutonium by filtration through a very fine filter. However the

137

Cs and

Sr will need

to be removed using an ion exchange resin. The americium in one water sample (room 001/3)

100

0246810

Contribution to radiotoxicity

Years

Pu Am Cm

Figure 32. The relative contri-

bution of plutonium, americium

and curium to the radiotoxicity

of transuranium elements

released by Chernobyl.

Table 20. Plutonium isotope signatures for Chernobyl and the Fukushima reactors.

Reactor Atomic percentage

238

239

240

241

242

Chernobyl 4 0.320 61.9 27.5 9.2 1.08 0.0451

Fukushima 1 1.37 64.8 22.0 10.8 0.814 0.134

Fukushima 2 1.13 64.8 20.7 11.3 0.535 0.111

Fukushima 3 1.08 64.8 23.3 9.72 0.535 0.104

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 84 of 100

behaved in a similar manner to the plutonium, while the americium in the water sample from room

012/13 was more able to pass through the filter (only 18% removed by filtration) (Rudenko & Khan,

2005). Odintsov et al. reported that the pH of the water from the object shelter was between 8 and 10

and that the carbonate and hydrogen carbonate anions were present. This combination of pH and

carbonate explains the solubility of the uranium as uranium(VI) forms water soluble anionic carbo-

nate complexes such as [UO

(CO

)

]

(n−2) −

. The pH of the water is so high that americium and curium

should be extensively hydrolysed to form hydroxides or other compounds.

The chemical form of the cesium, strontium, uranium, plutonium and americium was subject to

a more detailed examination by Rudenko and Khan (2005a), they were able to measure separately

the amounts of the radionuclides in the different particle size and ionic forms. As expected much

of the cesium was in the form of cations and the vast majority of the uranium was in an anionic

form. While the plutonium was as expected largely in the form of particles, the finding which

surprised me was that much of the americium was in an anionic form. I expect that the plutonium

was in the form of some polymer, it is well known that plutonium compounds can form polymers

when the acid concentration is low (Bell, Costanzo, & Biggers, 1973). The plutonium in soil at Rocky

Flats (Lopresti, Conradson, & Clark, 2007) and Taranaki (Maralinga, Australia) (Ikeda-Ohno et al.,

2016) is in the form of particles of tetravalent plutonium. It has also been found that plutonium(V/

VI) can react with hematite colloids to form very insoluble nanoparticles of consisting of PuO

·H

O on the surface of the particles of the iron mineral (Romanchuk et al., 2013). Rather than the

oxide particles containing plutonyl (O=Pu=O) plutonium atoms in the (V) or (VI) state it has been

found by EXAFS that the increased oxidation is spread over multiple atoms (Ekberg, Larsson,

Skarnemark, & Ödegaard-Jensen, 2013). The same paper in Dalton indicates that storage for

5 years of colloidal plutonium (94.4%

239

Pu, 5.5%

240

Pu and 0.1%

241

Pu) causes the appearance

of smaller colloids. It can be reasoned that inside the object shelter at Chernobyl that similar

plutonium colloids (or nanoparticles) have formed. These can be more mobile in soil than ionic

plutonium. Under some conditions the formation of colloidal particles increases the mobility of

plutonium (Wolfsberg et al., 2017) and some other metals.

The americium may be in the form of anionic complexes of carboxylates, at Oak Ridge (USA)

close to a transuranic waste store the migration of actinides (

241

Am and

244

Cm) has been observed

(McCarthy, Sanford, & Stafford, 1998). The saprolite minerals which are present in the site have a

very high affinity for europium and americium as long as “natural organic matter”is absent. But in

the field it has been shown that the americium, curium and neodymium are very mobile. This

mobility is thought to be due to the organic materials.

In a paper about electrophoresis-ICPMS experiments it was shown that europium binds to humic

acids. One of the problems is that humic acids are very large macromolecules which are poly-

carboxylic acids. Thus there is not a “humic acid”but many humic acids. It can be reasoned that if

the water in the basement of the Chernobyl accident site contained some humic acids then the

americium would be bound by some of the carboxylic acid groups, some of the other carboxylic

Table 21. Activity ratios in the water samples from the basement of unit 4 of Chernobyl and

the fuel.

Flow

direction

Room

238

Pu/

239

+240

241

Am/

239

+240

244

Cm/

239

+240

244

Cm/

241

North 001/3 0.502 11 0.51 0.046

South 12/7 0.520 11 0.54 0.048

East 406/2 0.446 3.7 0.13 0.027

Southeast 14/2 0.476 3.6 0.12 0.034

Fuel 0.504 1.5 0.078 0.050

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 85 of 100

acid groups will deprotonate in the alkaline water and thus make the americium-humic acid

complex an anion.

The use of europium as a surrogate for americium is an interesting matter, often it is assumed

that the lanthanide above a give actinide will be a good surrogate. When considering actinide

chemistry it can be argued that the results of an experiment are more relevant if the actinide

concerned is used rather than a surrogate. But as many of the actinides are very radiotoxic alpha

emitters so sometimes it is more reasonable to do an experiment to investigate an effect using

either a less radiotoxic beta emitter or even a nonradioactive metal. But sometimes the lanthanide

above the actinide is a poor choice, for example above plutonium is samarium. It should be clear

that while plutonium can exist in an oxidation state of +6 that the maximum oxidation state of

samarium is only +3. In the case of plutonium for the purpose of studying the dioxide, thorium and

cerium are better surrogates. Recently it has been argued that neodymium(III) is a better surro-

gate for americium(III) as the size of the cations (1.161 and 1.157 Å respectively) are more similar

than those of europium(III) (1.116 Å) and americium(III) (Lundberg & Persson, 2016). Incidentally

europium(III) may well be a better surrogate for einsteinium(III) (1.116 Å) than holmium(III).

However of the early and middle lanthanides very few have a convenient radionuclide suitable for

use as a radiotracer. The ideal radiotracer will be something cheap, easy to make, easy to detect

(gamma emitters are easier to count than pure beta emitters) (Table 22).

While nuclides with a mass of 152 and 154 can be formed by nuclear fission the stable

152

and

154

Sm will minimize the formation of

152

Eu and

154

Sm by simple nuclear fission. This is because

the main fission products (

152

Pr and

152

Nd) with this mass are more neutron rich nuclides than the

europium. Another method for the formation of

152

Eu is the neutron activation of the

151

Eu formed

as a stable fission product in the reactor. The kinetics of the formation of this stable

151

Eu will be a

little complex as its precursor

151

Sm has a long half-life (90 years). Also

151

Sm has a large cross

section for thermal neutrons (>10,000 barns) so in a reactor with a high thermal neutron flux it

might not survive long enough to undergo the beta decay into

151

Eu. The cross section for the n.2n

Table 22. Details of radiotracers of the lanthanides.

Metal Nuclide Half-life Comments

137

La 60,000 years Could be made from barium in a cyclotron

140

La 1.7 days Daughter of

140

Ba, fission product

144

Ce 285 days Fission product (a bit short lived)

143

Pr 14 days Fission product (shor tlived)

144

Nd 2.3 × 10

years Very low specific activity

147

Nd 11 days Fission product or by neutron activation (short lived)

150

Nd >1.1 × 10

years Very low specific activity

147

Pm 2.6 years Fission product or by neutron activation of

146

151

Sm 90 years Fission product or by neutron activation of

150

152

Eu 13.5 years Neutron activation of

151

154

Eu 8.6 years Fission product or by neutron activation of

153

155

Eu 4.8 years Fission product

148

Gd 75 years Cyclotron (alpha) on samarium

151

Gd 124 days Neutron activation of

150

153

Gd 240 days Neutron activation of

152

157

Tb 71 years Cyclotron (p) on gadolinium

158

Tb 180 years Cyclotron (p) on gadolinium

160

Tb 72 days Neutron activation of

159

Dy 144 days Neutron activation of

158

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 86 of 100

reaction on

153

Eu is very small unless the neutron energy is very high (>10 MeV) so it is unlikely

that much

152

Eu will be formed by spallation of neutrons from

153

Eu.

While the fission might be a poor source of

152

Eu and

154

Eu, it can form for other reasons inside a

nuclear reactor. Some reactors use europium in their control rods, for example some Russian naval

propulsion reactors use such control rods (Klochkov, Risovanyi, Vaneev, & Dorofeev, 2002). Also in

PWRs burnable poisons are used to reduce the change in the reactivity of the fuel during its life, a

series of different materials have been considered as burnable poisons (Galahom, 2017). Gadolinium

is commonly used as

155

Gd and

157

Gd have truly immense cross sections for thermal neutrons. As

the burnable poison is bombarded with neutrons these two isotopes of gadolinium are converted

into

156

Gd and

158

Gd which have much smaller cross sections for neutrons which might make this

seem like the perfect element for a burnable poison. However the neutron activation of

154

Gd and

156

Gd will generate fresh

155

Gd and

157

Gd which will tend to poison the fuel towards the end of the

life of the fuel when the poisoning is no longer desired. While stable europium has a smaller cross

section for thermal neutrons than some of the gadolinium isotopes it can be used as a burnable

poison according to Galahom. Galahom expresses the view that for a fuel which spends a long time

in a reactor that europium may be superior to gadolinium as a burnable poison (Table 23).

If we consider europium and gadolinium in a thermal neutron flux then it is possible to work out

what will happen, while the gadolinium will tend to undergo neutron capture to form heavier

isotopes it will form no radionuclide with a half-life of greater than 1 year. Also the stable

158

with a small cross section for neutrons will tend to reduce the amount of radioactivity which is

formed in the gadolinium. In contrast many of the europium isotopes with high neutron cross

sections form on activation radioactive isotopes of europium. If we ignore radiation damage due to

the intense neutron and gamma flux in a reactor then it can be reasoned that the Gd

will be

chemically unchanged as it performs this useful function in the fuel. Galahom expresses the view

that pyrex (borosilicate) glass is also a good burnable neutron poison, one disadvantage of boron

containing poisons is that on bombardment with neutrons they form helium gas.

It can be reasoned that if europium containing parts are used as core components that

152

and

154

Eu will form in the core, also even without a deliberate addition of europium the fission

Table 23. Details of europium and gadolinium isotopes.

Nuclide Thermal cross section

(barns)

Half-life (years) Abundance in natural

metal (%)

151

Eu 9,198 Stable 47.9

152

Eu 12,774 13.5 0

153

Eu 313 Stable 52.2

154

Eu 1,842 8.6 0

155

Eu 3,758 4.8 0

156

Eu 100 15 days 0

152

Gd 1,056 1.08 × 10

0.2

153

Gd 22,334 240 days 0

154

Gd 85 Stable 2.18

155

Gd 60,889 Stable 14.80

156

Gd 2.2 Stable 20.47

157

Gd 254,078 Stable 15.65

158

Gd 2.5 Stable 24.84

159

Gd –18.5 h 0

160

Gd 0.8 Stable 21.86

161

Gd –4 min 0

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 87 of 100

process will generate

155

Eu. As a result I conclude that the europium is very relevant to the study

of used fuels and reactor accidents. As a less toxic surrogate for

241

Am, I reason that while not

perfect that

152

Eu is a useful mimic.

While most attention regarding actinides and nuclear accidents has been payed to the trans-

uranic elements uranium can pose a threat. It is important to keep in mind that natural and

depleted uranium has a small ability to pose a threat. The problem uranium isotope is

232

U, this

can be formed in a range of different ways. The bombardment of

232

Th by neutrons can form

233

by simple neutron capture, the

233

Th then decays via

233

Pa to the fissile nuclei

233

U. However high

energy neutrons can form

231

Th by a n.2nreaction. The

231

Th decays (t

= 26 h) by beta emission

into

231

Pa which has a long half-life (32,760 years). By neutron capture it is converted into

232

which decays by beta decay (t

= 1.3 days) into

232

U. The decay of

234

U forms

230

= 75,400 years) which undergoes neutron capture to form

231

Th which then by means of

beta decays and neutron capture forms

232

U. Fast neutrons can form

232

U from

233

U and

235

Uin

n.2nand n.4nreactions. The n.4nreaction on

235

U together with the pathway starting with

234

Uis

responsible for forming the majority of

232

UinUO

fuel (Yamamoto & Okumura, 2014).

In MOX made from plutonium and depleted uranium the main source of

232

U is a pathway starting

with

238

U. What happens is that fast neutrons create

237

Ubyan.2nreaction (Yamamoto & Okumura,

2014). The

237

U(t

= 6.8 days) decays by beta emission to

237

Np (t

= 2,144,000 years). Then a second

n.2nreaction forms

236m

Np (t

= 22.5 h) which decays into

236

Pu (t

= 2.9 years) which in turn decays

by alpha emission into

232

U. If we start with MOX made using uranium recovered from a PUREX plant

then the pathway starting with

238

U is important but a pathway starting with neutron activation of

236

U is even more important (Yamamoto & Okumura, 2014). If we were to make a MOX fuel and cram

into it neptunium (

237

Np) and americium (

241

Am and

243

Am) then even more

232

U would form in the

fuel. The

232

U(t

= 69 years) will decay by alpha emission to

228

Th (1.9 years) which likewise decays by

alpha emission to form

224

Ra (3.7 days) which emits an alpha particle to form

220

Rn (thoron). Already

at the Chernobyl accident site inside the object shelter the daughters of

220

Rn have started to pose a

threat to workers (Ogorodnikov et al., 2009). As

232

U has a longer half-life than

137

Cs and

Sr as the

cesium and strontium decay away the thoron daughters will become more important. I predict thatat

Fukushima in the future that the thoron problem will also become one of the dominantthreats at the

site unless the fuel is recovered in the near future.

Funding

The author received no direct funding for this research.

Competing interests

The author declares no competing interests.

Author details

Mark R. St J. Foreman

E-mail: Foreman@chalmers.se

ORCID ID: http://orcid.org/0000-0002-1491-313X

Industrial Materials Recycling, Department of Chemistry

and Chemical Engineering, Chalmers University of

Technology, Göteborg, Sweden.

Citation information

Cite this article as: Reactor accident chemistry an update,

Mark R. St J. Foreman, Cogent Chemistry (2018), 4: 1450944.

Notes

1. The reader can be forgiven for asking why I expressed

myself in Locomotive BASIC, the reason is that as a

youngster it was a computer language which I was heavily

exposed to. Having written FORTRAN asan undergraduate

I came to the conclusion that the two were similar.

2. I will not discuss in detail the ethical issues asso-

ciated with the human radiation and radiaoctivity

experiments performed many years ago in the USA.

For the plutonium injection experiments the intention

was to inject people who were terminally ill with

plutonium to determine how it would behave in a

human body. It is noteworthy that in this experiment

(and some others) that informed consent was not

obtained from the human test subjects. It is note-

worthy that at least one unethical experiment was

resulted in a successful lawsuit by family members

against researchers, the University of Cincinnati, and

the City of Cincinnati.

3. Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon,

Nitrogen, Oxygen, Flourine, Neon, Sodium, Magnesium,

Aluminium, Silicon, Phosphorus, Sulphur, Chlorine,

Argon, Scandium, Titanium, Vanadium, Chromium,

Manganese, Iron, Cobalt, Nickel, Copper, Zinc,

Ruthenium, Rhodium, Palladium, Silver, Cadmium,

Osmium, Iridium, Platinum, Gold, Mercury, Thallium,

Radon, Radium, Actinium, Thorium, Protactinium,

Uranium, Neptunium, Plutonium, Americium, Curium.

4. I have made the simple assumption that testicular

dose is proportional to the activity of plutonium

injected into the mouse and the time between the

injection and mating with the female mouse.

5. Huet, Trompier, Clairand, Queinnec, and Bottollier-

Depois (2008).

References

Abe, K., DonSantos, R., Gauvain, J., Jones, C.G., Jouve, A.,

Ramirez, M.L., ...,Wheatley, J. (2013). The

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 88 of 100

international nuclear and radiological event scale,

user’s manual 2008 edition (2013 extended edition).

Austria: IAEA. Retrieved from https://www-pub.iaea.

org/MTCD/Publications/PDF/INES2013web.pdf

Abe, Y., Iizawa, Y., Terada, Y., Adachi, K., Igarashi, Y., &

Nakai, I. (2014). Detection of uranium and chemical

state analysis of individual radioactive microparticles

emitted from the Fukushirna nuclear accident using

multiple synchrotron radiation X-ray analyses.

Anayltical Chemistry,86, 8521–8525. doi:10.1021/

ac501998d

Adachi, K., Kajino, M., Zaizen, Y., & Igarashi, Y. (2013).

Emission of spherical cesium-bearing particles from

an early stage of the Fukushima nuclear accident.

Scientific Reports,3, 2554. doi:10.1038/srep02554

Adams, E. G., & Simmons, N. T. (1951). The determination

of carbon monoxide by means of iodine Pentoxide.

Journal of Applied Chemistry,1, S20–S40.

Agopiantz, M., Elhanbali, O., Demore, B., Cuny, T.,

Demarquet, L., Ndiaye, C., . .. Klein, M. (2016). Thyroid

side effects prophylaxis in front of nuclear power

plant accidents. Annales d Endocrinologie,77,1–6.

doi:10.1016/j.ando.2015.12.003

Aguiar, J. C., Galiano, E., & Fernandez, J. (2006). Peak

efficiency calibration for attenuation corrected

cylindrical sources in gamma ray spectrometry by

the use of a point source. Applied Radiation and

Isotopes,64, 1643–1647. doi:10.1016/j.

apradiso.2006.05.014

Ainsbury, E. A., Bakhanova, E., Barquinero, J. F., Brai, M.,

Chumak, V., Correcher, V., .. . Rothkamm, K. (2011).

Review of retrospective dosimetry techniques for exter-

nal ionising radiation exposures. Radiation Protection

Dosimetry,147, 573–592. doi:10.1093/rpd/ncq499

Akleyev, A. V., Krestinina, L. Y., Degteva, M. O.,& Tolstykh, E.

I. (2017). Consequences of the radiation accident at

the Mayak production association in 1957 (the

‘Kyshtym Accident’). Journal of Radiological Protection,

37,R19–R42. doi:10.1088/1361-6498/aa7f8d

Alam, F., Soloway, A. H., & Barth, R. F. (1987). Boronation of

antibodies with mercaptoundecahydro-closo-dodeca-

borate(2-) anion for potential use in boron neutron-

capture therapy. Applied Radiation and Isotopes,38,

503–506. doi:10.1016/0883-2889(87)90195-X

Alves, C. A., Evtyugina, M., Cerqueira, M., Nunes, T., Duarte,

M., & Vicente, E. (2015). Volatile organic compounds

emitted by the stacks of restaurants. Air Quality

Atmosphere and Health,8, 401–412. doi:10.1007/

s11869-014-0310-7

Amiro, B. D., Sheppard, S. C., Johnston, F. L., Evenden,

W.G.,&Harris,D.R.(1996). Burning radionuclide

question: What happens to iodine, cesium and

chlorine in biomass fires? The Science of the Total

Environment,187,93–103. doi:10.1016/0048-9697

(96)05125-X

Andreev, G., Antipin, Y., Bennett, B., Chizhikov, V.,

Gonzalez, A. J., Gordeev, A., . . . Webb, G. A. M. (1998).

The radiological accident in the reprocessing plant at

Tomsk. Austria: IAEA.

Aneheim, E., Ekberg, C., & Foreman, M. R. S. (2012).

Aqueous complexation of palladium to prevent pre-

cipitation and extraction in a group actinide extrac-

tion system. Hydrometallurgy,115,71–76.

doi:10.1016/j.hydromet.2011.12.018

Anonymous. (2011). Retrieved October 26, 2017, from

https://wonder.cdc.gov/mmwr/mmwrmort.asp

Anonymous. (1955). Commercial film-badge services.

Nucleonics,13(2), 86–87.

Anonymous. (2006). Retrieved from https://www.indepen

dent.ie/irish-news/sellafield-drama-a-bizarre-slur-

26391469.html

Anonymous. (2011, November 11). Atomic radiation is

more harmful to women. Nuclear Monitor, issue

#736, number 6192, 7.

Antonopoulos-Domis, M., Clouvas, A., & Gagianas, A.

(1991). Radiocesium dynamics in fruit-trees following

the Chernobyl accident. Health Physics,61, 837–842.

doi:10.1097/00004032-199112000-00015

Antonopoulos-Domis, M., Clouvas, A., & Gagianas, A.

(1996). Long term radiocesium contamination of fruit

trees following the Chernobyl accident. Health

Physics,71,910–914. doi:10.1097/00004032-

199612000-00007

Arima, T., Masuzumi,T., Furuya, H., Idemisu, K., & Inagaki, Y.

(2002). Reaction of Zircaloy-4 with tellurium under dif-

ferent oxygen potentials. Journal of Nuclear Materials,

301,90–97. doi:10.1016/S0022-3115(02)00711-0

Aubert, M., Calais, D., & Le Beuze, R. (1975). Role of iodine

in development of reaction between fuel and its 316

stainless-steel cladding in reactors. Journal of

Nuclear Materials,58, 257–277. doi:10.1016/0022-

3115(75)90118-X

Avramenko, M. I., Averin, A. N., Drozhko, E. G., Glagolenko,

Y. V., Filin, V. P., Loboiko, B. G., . . . Romanov, G. N.

(2000). Radiation accident of 1957 and Eastern-Urals

radioactive trace: Analysis of measurement data and

laboratory experiments. Atmospheric Environment,

34, 1215–1223. doi:10.1016/S1352-2310(99)00303-9

Ayrault, S., Jimenez, B., Garnier, E., Fedoroff, M., Jones, D.

J., & Loos-Neskovic, C. (1998). Sorption mechanisms

of cesium on (Cu2FeII)-Fe-II(CN)(6) and Cu-3(II)[Fe-

III(CN)(6)](2): Hexacyanoferrates and their relation

to the crystalline structure. Journal of Solid State

Chemistry,141, 475–485. doi:10.1006/jssc.1998.7997

Baba, Y., Eguchi, T., & Inoue, K. (1986). Solvent-extraction

of palladium with dihexyl sulfide. Journal of Chemical

Engineering of Japan,19, 361–366. doi:10.1252/

jcej.19.361

Baenziger, N. C., Rundle, R. E., Snow, A. I., & Wilson, A. S.

(1950). Compounds of uranium with the transition

metals of the 1st long period. Acta Crystallographica,

3,34–40. doi:10.1107/S0365110X50000082

Barber, H. H., & Kolthoff, I. M. (1929). Gravimetric deter-

mination of sodium by the uranyl zinc acetate

method. II. Application in the presence of rubidium,

cesium, potassium, lithium, phosphate or arsenate.

Journal of the American Chemical Society,51, 3233–

3237. doi:10.1021/ja01386a008

Barth, R. F., Soloway, A. H., Fairchild, R. G., & Brugger, R. M.

(1992). Boron neutron-capture therapy for cancer—

realities and prospects. Cancer,70, 2995–3007.

Baxendale, J. H., & Smithies, D. (1956). Die

Strahlenchemie in Wasser gelöster organischer

Verbindungen [The radiation chemistry in water of

dissolved organic compounds]. Zeitschrift für

Physikalische Chemie (Frankfurt),7, 242–264.

doi:10.1524/zpch.1956.7.3_4.242

Beahm, E. C. (1987). Tellurium behavior in containment

under light water reactor accident conditions.

Nuclear Technology,78, 295–302. doi:10.13182/

NT87-A15995

Beck, H. L. (1980). Exposure rate conversion factors for

radionuclides deposited on the ground. New York, NY:

Environmental Measurements Laboratory,

Department of Energy.

Bell, J. C., Bridge, H., Cottrell, A. H., Greenough, G. B.,

Reynolds, W. N., & Simmons, J. H. W. (1962). Stored

energy in graphite of power-producing reactors.

Philosophical Transactions of the Royal Society of

London,254, 361–395. doi:10.1098/rsta.1962.0002

Bell, J. T., Costanzo, D. A., & Biggers, R. E. (1973).

Plutonium polymerization. 2. Kinetics of plutonium

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 89 of 100

polymerization. Journal Inorganic Nuclear Chemical,

35, 623–628. doi:10.1016/0022-1902(73)80576-7

Bernard, F., McGillen, M. R., Fleming, E. L., Jackman, C. H.,

& Burkholder, J. B. (2015). CBrF3 (Halon-1301): UV

absorption spectrum between 210 and 320 K, atmo-

spheric lifetime, and ozone depletion potential.

Journal of Photochemistry and Photobiology A:

Chemistry, 306, 13–20. doi:10.1016/j.

jphotochem.2015.03.012

Bianchi, A. P., & Varney, M. S. (1993). Sampling and ana-

lysis of volatile organic-compounds in estuarine air

by gas-chromatography and mass-spectrometry.

Journal of Chromatography,643,11–23. doi:10.1016/

0021-9673(93)80536-H

Boeyens, J. C. A., McDougal, G. J., & Van R. Smit, J. (1976).

Crystallographic study of ammonium-potassium 12-

molybdophosphate ion-exchange system. Journal of

Solid State Chemistry,18, 191–199. doi:10.1016/

0022-4596(76)90095-5

Bonjoch, J., Drew, M. G. B., Gonzalez, A., Greco, F., Jawaid,

S., Osborn, H. M. I., . . . Yaqoob, P. (2008). Synthesis

and evaluation of novel boron-containing complexes

of potential use for the selective treatment of

malignant melanoma. Journal of Medicinal

Chemistry,51, 6604–6608. doi:10.1021/jm8007745

Borzelleca, J. F. (2000). Paracelsus: Herald of modern

toxicology. Toxicological Sciences,53,2–4.

doi:10.1093/toxsci/53.1.2

Bosland, L., Funke, F., Girault, N., & Langrock, G. (2008).

Paris project: Radiolytic oxidation of molecular iodine

in containment during a nuclear reactor severe

accident. Part 1. Formation and destruction of air

radiolysis products—Experimental results and mod-

elling. Nuclear Engineering and Design,238, 3542–

3550. doi:10.1016/j.nucengdes.2008.06.023

Bradley, L. (2006). Retrieved from https://www.indepen

dent.ie/irish-news/nuclear-docudrama-slammed-by-

minister-26411084.html

Bredig, M. A., Johnson, J. W., & Smith, W. T. (1955). Miscibility

of liquid metals with salts. 1. The sodium–sodium

halide systems. Journal of the American Chemical

Society,77,3

07–312. doi:10.1021/ja01607a016

Broda, R., Mietelski, J. W., & Sieniawski, J. (1992).

Radioactive SB-125 and Co-60 in ruthenium hot par-

ticles from Chernobyl fallout. Journal of

Radioanalytical and Nuclear Chemistry Letters,166,

173–180. doi:10.1007/BF02164740

Buck, E. C., Mausolf, E. J., McNamara, B. K., Soderquist, C.

Z., & Schwantes, J. M. (2016). Sequestration of

radioactive iodine in silver-palladium phases in

commercial spent nuclear fuel. Journal of Nuclear

Materials,482, 229–235. doi:10.1016/j.

jnucmat.2016.10.029

Bujdosó, E. (1987). The Chernobyl reactor accident.

Journal of Radioanalytical and Nuclear Chemistry,

116, 223–231. doi:10.1007/BF02037225

Buki, G., & Bede, G. (1965). Critical size and flux distribu-

tion of hollow spherical and cylindrical reactors.

Periodica Polytechnica-Engineering,9, 227–242.

Busk, R. S. (1952). Effect of temperature on the lattice

parameters of magnesium alloys. Journal of Metals,

4, 207–209.

Buxton, G. V., Greenstock, C. L., Helman, W. P., & Ross, A.

B. (1988). Critical-review of rate constants for reac-

tions of hydrated electrons, hydrogen-atoms and

hydroxyl radicals (∙OH/ ∙O−) in aqueous-solution.

Journal of Physical and Chemical Reference Data,17,

513–886. doi:10.1063/1.555805

Cahn, R. W. (1977). Metal bites metal. Nature,265,11–12.

doi:10.1038/265011b0

Caldicott, H. (2006). Nuclear power is not the answer. New

York, NY: The New Press.

Carbaugh, E. H., Lynch, T. P., Antonio, C. L., & Medina-Del

Valle, F. (2010). Twenty-four years of follow-up for a

Hanford plutonium wound case. Health Physics,99,

483–494. doi:10.1097/HP.0b013e3181d96381

Cattanach, B. M., Papworth, D., Patrick, G., Goodhead, D. T.,

Hacker, T., Cobb, L., & Whitehill,E. (1998). Investigation

of lung tumour induction in C3H/HeH mice, with and

without tumour promotion with urethane, following

paternal X-irradiation. Mutation Research,403,1–12.

doi:10.1016/S0027-5107(97)00322-9

Cattanach, B. M., Patrick, G., Papworth, D., Goodhead, D.

T., Hacker, T., Cobb, L., & Whitehill, E. (1995).

Investigation of lung-tumor induction in balb cj mice

following paternal X-irradiation. International Journal

of Radiation Biology, 67, 607–615. doi:10.1080/

09553009514550721

Chamberlain, A. C., Eggleton, A. E. J., Megaw, W. J., &

Morris,J.B.(1963). Physical chemistry of iodine

and removal of iodine from gas streams. Reactor

Science and Technology (Journal of Nuclear Energy

Parts A/B),17,519–550. doi:10.1016/0368-3230(63)

90066-1

Chapman, L. R., & Holcombe, C. E., JR. (1984). Revision of

the uranium iron phase-diagram. Journal of Nuclear

Materials,126, 323–326. doi:10.1016/0022-3115(84)

90046-1

Chase, M. W. (1998). NIST-JANAF themochemical tables,

fourth edition. Journal Physical Chemical Ref Data,

Monograph 9, 1–1951.

Chattopadhyay, G., & Juneja, J. M. (1993). A thermodynamic

database for tellurium-bearing systems relevant to

nuclear technology. Journal of Nuclear Materials,202,

10–28. doi:10.1016/0022-3115(93)90024-S

Cheng, T., & Tortorelli, P. F. (2013). Silicon carbide oxida-

tion in high-pressure steam. Journal American Ceram

Social,96, 2330–2337. doi:10.1111/jace.12328

Chubb. Retrieved from http://www.chubb.ie/Pages/

ChubbFirePyrometPowderExtinguisher.aspx (Note

that COSHH paperwork for the pyromet system

existed in 2003).

Clough, W. S., & Fraser, A. (1973). Tellurium, cesium,

iodine and methyl-iodide in fast-reactors. Journal of

Nuclear Energy,27,1–14. doi:10.1016/0022-3107(73)

90050-6

Cockerell, J. (2014). Retrieved from http://www.indepen

dent.co.uk/news/uk/crime/twitter-trolls-isabella-sor

ley-and-john-nimmo-jailed-for-abusing-feminist-

campaigner-caroline-criado-9083829.html

Coggle, J. E. (1971). Biological effects of radiation. London:

Wykeham Publications (London) Ltd (A member of

the Taylor and Francis Group).

Cosgrove, G. E., Selby, P. B., Upton, A. C., Mitchell, T. J.,

Steele, M. H., & Russell, W. L. (1993). Life-span and

autopsy findings in the 1st-generation offspring of

x-irradiated male-mice. Mutation Research, 319, 71–

79. doi:10.1016/0165-1218(93)90032-9

Cox, J. D., Wagman, D. D., & Medvedev, V. A. (1984).

CODATA Key values for thermodynamics (Vol. 1). New

York, NY: Hemisphere Publishing Corp.

Coy, K., Ghosh, P., Kaituri, M., McCready-Shea, S.,

Oresegun, M., Piccone, J., . . . Zamora, F. (1998).

Lessons learned from accidents in industrial radio-

graphy. Safety Reports Series No. 7. Vienna:

International Atomic Energy Agency, IAEA.

Cubicciotti, D., & Sanecki, J. E. (1978). Characterization of

deposits on inside surfaces of LWR cladding. Journal

of Nuclear Materials,78,96–111. doi:10.1016/0022-

3115(78)90508-1

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 90 of 100

Czerwinski, F. (2004). The early stage oxidation and eva-

poration of Mg–9%Al–1%Zn alloy. Corrosion Science,

46, 377–386. doi:10.1016/S0010-938X(03)00151-3

Daher, A., Varin, M., Lamontagne, Y., & Oth, D. (1998).

Effect of pre-conceptional external or internal irra-

diation of N5 male mice and the risk of leukemia in

their offspring. Carcinogenesis,19, 1553–1558.

doi:10.1093/carcin/19.9.1553

Dale, R. G. (1985). The application of the linear-quadratic

dose-effect equation to fractionated and protracted

radiotherapy. The British Journal of Radiology,58,

515–528. doi:10.1259/0007-1285-58-690-515

de González, B., Ntowe, E., Kitahara, C. M., Gilbert, E.,

Miller, D. L., Kleinerman, R. A., & Linet, M. S. (2016).

Long-term mortality in 43 763 US radiologists com-

pared with 64 990 US psychiatrists. Radiology,281,

847–857. doi:10.1148/radiol.2016152472

DeBoer, R., & Cordfunke, E. H. P. (1997). The chemical

form of fission product tellurium during reactor

accident conditions. Journal of Nuclear Materials,

240, 124–130. doi:10.1016/S0022-3115(96)00600-9

Denloye, A. O., Gasner, L. L., & Adamchak, F. R. (1984).

Thermodynamic analysis of a fluidized-bed combus-

tor. Thermochimica Acta,75,9–22. doi:10.1016/0040-

6031(84)85002-9

DiLemma, F. G., Colle, J. Y., Benes, O., & Konings, R. J. M.

(2015). A separate effect study of the influence of

metallic fission products on CsI radioactive release

from nuclear fuel. Journal of Nuclear Materials,465,

499–508. doi:10.1016/j.jnucmat.2015.05.037

Ding, H. L., & Hopke, P. K. (1993). HO(X) production due to

radon decay in air. Journal of Atmospheric Chemistry,

17, 375–390. doi:10.1007/BF00696855

Dunster, H. J., Howells, H., & Templeton, W. L. (2007).

District surveys following the windscale incident,

October 1957. Journal of Radiological Protection,27,

217–230. doi:10.1088/0952-4746/27/3/001

Eckerman, K., Harrison, J., Menzel, H.-G., & Clement, C. H.

(2012). Compendium of Dose Coefficients based on

ICRP Publication 60. Annals ICRP,41,1–130.

doi:10.1016/j.icrp.2012.06.038

Edvarson, K., Löw, K., & Sisefsky, J. (1959). Fractionation

phenomena in nuclear weapons debris. Nature,184,

1771–1774. doi:10.1038/1841771a0

Edwards, D. J., & Bernier, S. M. (1996). Naringin and nar-

ingenin are not the primary CYP3A inhibitors in

grapefruit juice. Life Sciences,59, 1025–1030.

doi:10.1016/0024-3205(96)00417-1

Eeles, W. T., & Sutton, A. L. (1963). X-ray determination of

atomic positions in alpha-uranium at 22 degrees C

and 600 degrees C. Acta Crystallographica,16, 575.

doi:10.1107/S0365110X63001511

Ekberg, C., Larsson, K., Skarnemark, G., & Ödegaard-

Jensen, A. (2013). The structure of plutonium(IV)

oxide as hydrolysed clusters in aqueous suspensions.

Dalton Transactions,42, 2035–2040. doi:10.1039/

C2DT32185H

Elkind, M. M., Suttongi, H., Moses, W. B., Alescio, T., &

Swain, R. W. (1965). Radiation response of mamma-

lian cells grown in culture. V. Temperature depen-

dence of repair of X-ray damage in surviving cells

(aerobic and hypoxic). Radiation Research, 25, 359–

376. doi:10.2307/3571978

Endo, A., Kikuchi, M., Izawa, S., & Ikezawa, Y. (1995).

Characteristics of the chemical forms of C-11, N-13,

and O-15 induced in air by the operation of A 100-

MEV electron linear-accelerator. Health Physics,68,

80–88. doi:10.1097/00004032-199501000-00010

Endo, A., Sato, K., Noguchi, H., Su, T. T., Furuichi, I. S.,

Kanda, Y., & Oki, Y. (2003). Study of particle size

distribution and formation mechanism of radioactive

aerosols generated in high-energy neutron fields.

Journal of Radioanayltical and Nuclear Chemistry,

256, 231–237. doi:10.1023/A:1023925031655

Evangeliou, N., Zibtsev, S., Myroniuk, V., Zhurba, M.,

Hamburger, T., Stohl, A., . . . Kireev, S. I. (2016).

Resuspension and atmospheric transport of radio-

nuclides due to wildfires near the Chernobyl Nuclear

Power Plant in 2015: An impact assessment.

Scientific Reports,6, 26062. doi:10.1038/srep26062

Finch, G. L., Lundgren, D. L., Barr, E. B., Chen, B. T., Griffith,

W. C., Hobbs, C. H., . . . Mauderly, J. L. (1998). Chronic

cigarette smoke exposure increases the pulmonary

retention and radiation dose of Pu-239 inhaled as

(PuO2)-Pu-239 by F344 rats. Health Physics,75, 597–

609. doi:10.1097/00004032-199812000-00003

Finsterer, J. (2002). Earl Grey tea intoxication. The Lancet,

359(9316), 1484. doi:10.1016/S0140-6736(02)08436-2

Fischer, P. (1967). Neutronenbeugungsuntersuchung der

strukturen Von MGAL2O4-und ZNAL2O4-spinellen in

abhangigkeit von der vorgeschichte [Neutron binding

study of the structures of MGAL2O4 and ZNAL2O4

spinelles in relation to the previous story]. Zeitschrift

fuer Kristallographie Kristallgeometrie Kristallphysik

and Kristallchemie,124, 275–302. doi:10.1524/

zkri.1967.124.4-5.275

Flowers, F. H. (1986). Dragons exhalations give clue to

Chernobyl. Nature,323, 208. doi:10.1038/323208a0

Foreman, M. R. S. (2015). An introduction to serious

nuclear accident chemistry. Cogent Chemistry,1.

doi:10.1080/23312009.2015.1049111

Franco, M. G., Correa, S. M., Marques, M., & Perez, D. V.

(2014). Emission of volatile organic compounds and

greenhouse gases from the anaerobic bioremediation

of soils contaminated with diesel. Water, Air and Soil

Pollution,225, 1879. doi:10.1007/s11270-014-1879-z

Friedland, E., Van der Berg, N. G., Matherbe, J. B.,

Hancke,J.J.,Barry,J.,Wendler,E.,&Wesch,W.

(2011). Investigation of silver and iodine transport

through silicon carbide layers prepared for nuclear

fuel element cladding. Journal of Nuclear Materials,

410,24–31.

Frunzke, J., Loschen, C., & Frenking, G. (2004). Why are

olefins oxidized by RuO4 under cleavage of the car-

boncarbon bond whereas oxidation by OsO4 yields

cis-diols? Journal of the American Chemical Society,

126, 3642–3652. doi:10.1021/ja039921a

Fuggle, J. C., Watson, L. M., Fabian, D. J., & Affrossman, S.

(1975). X-ray photoelectron studies of reaction of

clean metals (MG, AL,CR,MN) with oxygen and water-

vapor. Surface Science,49,61–76. doi:10.1016/0039-

6028(75)90328-3

Gaffney, R. J. (2000a). Retrieved from https://apps2.suf

folkcountyny.gov/legislature/resos/resos2000/

i1767-00.htm

Gaffney, R. J. (2000b). Retrieved from https://apps2.suf

folkcountyny.gov/legislature/resos/resos2000/

i1971-00.htm

Galahom, A. A. (2017). Study of the possibility of using

Europium and Pyrex alloy as burnable absorber in

PWR. Annals of Nuclear Energy,110, 1127–1133.

doi:10.1016/j.anucene.2017.08.052

Gale, R. P. (2012). Response to “an unexpected mortality

increase in the United States follows arrival of the

radioactive plume from Fukushima: Is there a corre-

lation?”International Journal of Health Services,42,

557–559. doi:10.2190/HS.42.3.l

Gall, M., Mahler,S., & Wirth, E. (1991).Transfer of CS-137 into

mothers milk. Journal of Environmental Radioactivity,

14,331–339. doi:10.1016/0265-931X(91)90023-9

Garger, E. K., Kashpur, V., Paretzke, H. G., & Tschiersch, J.

(1998). Measurement of resuspended aerosol in the

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 91 of 100

Chernobyl area—Part II. Size distribution of radioac-

tive particles. Environment Biophysics,36, 275–283.

doi:10.1007/s004110050082

Garger, E. K., Paretzke, H. G., & Tschiersch, J. (1998).

Measurement of resuspended aerosol in the

Chernobyl area Part III. Size distribution and dry

deposition velocity of radioactive particles during

anthropogenic enhanced resuspension. Radiational,

Environmental, Biophysics,37, 201–208. doi:10.1007/

s004110050118

Garland, J. A., & Wakefield, R. (2007). Atmospheric emis-

sions from the Windscale accident of October 1957.

Atmospheric Environment,41, 3904–3920.

doi:10.1016/j.atmosenv.2006.12.049

Gillett, N. A., Pool, R. R., Taylor, G. N., Muggenburg, B. A., &

Boecker, B. B. (1992). SR-90 induced bone-tumors in

beagle dogs—effects of route of exposure and dose-

rate. International Journal of Radiation Biology,61,

821–831. doi:10.1080/09553009214551701

Gillmore, G., Gharib, H. A., Denman, A., Phillips, P., &

Bridge, D. (2011). Radon concentrations in aban-

doned mines, Cumbria, UK: Safety implications for

industrial archaeologists. Natural Hazards and Earth

System Sciences,11, 1311–1318. doi:10.5194/nhess-

11-1311-2011

Gillmore, G. K., Phillips, P., Denman, A., Sperrin, M., &

Pearce, G. (2001). Radon levels in abandoned metal-

liferous mines, Devon, southwest England.

Ecotoxicology and Environmental Safety,49, 281–

292. doi:10.1006/eesa.2001.2062

Gordon, P. L., O’Dell, C., & Watkin, J. G. (1994). Synthesis

and energetic content of red oil. Journal of Hazardous

Materials,39,87–105. doi:10.1016/0304-3894(94)

00061-1

Gosse, S., & Gueneau, C. (2011). Thermodynamic assess-

ment of the palladium-tellurium (Pd-Te) system.

Intermetallics,19,621–629. doi:10.1016/j.

intermet.2010.12.014

Gowdamarajan, A., & Michler, R. E. (2000). Therapy for

primary cardiac tumors: Is there a role for heart

transplantation? Current Opinion in Cardiology,15,

121–125. doi:10.1097/00001573-200003000-00010

Grant, E. J., Brenner, A., Sugiyama, H., Sakata, R.,

Sadakane, A., Utada, M., . . . Ozasa, K. (2017). Solid

cancer incidence among the life span study of

atomic bomb survivors: 1958–2009. Radiation

Research,187, 513–537. doi:10.1667/RR14492.1

Greenpeace. (2006) Retrieved September 17, 2017, from

http://www.greenpeace.org/international/en/cam

paigns/nuclear/proliferation/plutonium/

Gribble, G. W. (1994). Natural organohalogens—many

more than you think. Journal Chemical Editors,71,

907–911. doi:10.1021/ed071p907

Gribble, G. W. (2003). The diversity of naturally produced

organohalogens. Chemosphere,52, 289–297.

doi:10.1016/S0045-6535(03)00207-8

Grubb, W. T. (1976). Nuclear fuel assembly and process.

US patent, 1976, US4097402 A.

Gupta, A., Andrews, K. L., McDaniel, K. M., Nagle, R. B., &

Bowden, G. T. (1999). Experimental induction of

rhabdomyosarcoma in mice with fractionated doses

of beta-irradiation. Journal of Cancer Research and

Clinical Oncology,125, 257–267. doi:10.1007/

s004320050272

Haley, B. M., Paunesku, T., Grdina, D. J., & Woloschak, G.

W. (2015). The increase in animal mortality risk fol-

lowing exposure to sparsely ionizing radiation is not

linear quadratic with dose. PLOS ONE,10, e0140989.

doi:10.1371/journal.pone.0140989

Harding, M., Manley, J., Wright, C., Buckland, C., Evans, C.,

Barschall, H., . . . Whipple, H. O. (1948). Radiation

doses in the Pajarito accident of May 21 1946, LA-687.

Los Alamos: Los Alamos Scientific Laboratory of the

University of California.

Hare, D., Tolmachev, S., James, A., Bishop, D., Austin, C.,

Fryer, F., & Doble, P. (2010). Elemental bio-imaging of

thorium, uranium, and plutonium in tissues from

occupationally exposed former nuclear workers.

Analytical Chemistry, 82, 3176–3182. doi:10.1021/

ac902650w

Harr, L. J. (2007). Precise calculation of complex radio-

active decay chains. Ohio: Air Force Institute of

Technology. http://dtic.mil/dtic/tr/fulltext/u2/

a469273.pdf

Harrison, M. T. (2014). Vitrification of high level waste in

the UK. Procedia Materials Science,7,10–15.

doi:10.1016/j.mspro.2014.10.003

Hicks, H. G. (1982). Calculation of the concentration of

any radionuclide deposited on the ground by offsite

fallout from a nuclear detonation. Health Physics,42,

585–600. doi:10.1097/00004032-198205000-00003

Horwitz, E. P., Chiarizia, R., & Dietz, M. L. (1992). A novel

strontium-selective extraction chromatographic

resin. Solvent Extraction and Ion Exchange,10, 313–

336. doi:10.1080/07366299208918107

Horwitz, E. P., Dietz, M. L., & Fisher, D. E. (1991).

Separation and preconcentration of strontium from

biological, environmental, and nuclear waste sam-

ples by extraction chromatography using a crown-

ether. Analytical Chemistry,63, 522–525.

doi:10.1021/ac00005a027

Hudson, M. J., Knowles, J. P., Harris, P. J. F., Jackson, D. B.,

Chinn, M. J., & Ward, J. L. (2004). The trapping and

decomposition of toxic gases such as hydrogen cya-

nide using modified mesoporous silicates.

Microporous and Mesoporous Materials,75, 121–128.

doi:10.1016/j.micromeso.2004.07.023

Huet, C., Trompier, F., Clairand, I., Queinnec, F., &

Bottollier-Depois, J. F. (2008). Physical dosimetric

reconstruction of a radiological accident at Fleurus

(Belgium) on 11 March 2006. Radiation

Measurements,43, 845–848. doi:10.1016/j.

radmeas.2007.12.018

Huh, C.-A. (1999). Dependence of the decay rate of Be-7 on

chemical forms. Earth and Planetary Science Letters,

171, 325–328. doi:10.1016/S0012-821X(99)00164-8

Hunt, G. J. (1998). Transfer across the human gut of

environmental plutonium, americium, cobalt, cae-

sium and technetium: Studies with cockles

(Cerastoderma edule) from the Irish Sea. Journal

Radiology Protection,18, 101–109. doi:10.1088/0952-

4746/18/2/005

Hutchinson, C. M., McGiffen, M. E., Oh, H. D., Sims, J. J., &

Becker, J. O. (2000). Efficacy of methyl iodide and

synergy with chloropicrin for control of fungi. Pest

Management Science,56, 413–418. doi:10.1002/

(ISSN)1526-4998

IAEA. (2014). INES Rating Interactive Learning Tool.

Retrieved from https://iec.iaea.org/inesrilt/

Ikeda-Ohno, A., Shahin, L. M., Howard, D. L., Collins, R. N.,

Payne, T. E., & Johansen, M. P. (2016). Fate of pluto-

nium at a former nuclear testing site in Australia.

Environmental Science & Technology,50, 9098–9104.

doi:10.1021/acs.est.6b01864

Inada, J. (2000). Radiological and environmental aspects

of the criticality accident in Tokai-mura. Radiation

Protection Dosimetry,92, 239–246. doi:10.1093/

oxfordjournals.rpd.a033277

Isetti, G. (1965). Ricerche sulla struttura della Brucite.

Periodico di Mineralogia,34, 327–335.

Ishimoto, S., Hirai, M., Ito, K., & Korei, Y. (1996). Thermal

conductivity of UO2-BeO pellet. Journal of Nuclear

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 92 of 100

Science and Technology,33, 134–140. doi:10.1080/

18811248.1996.9731875

Iwata, T. (1985). Fine-structure of wigner energy-release

spectrum in neutron-irradiated graphite. Journal of

Nuclear Materials,133–134, 361–364. doi:10.1016/

0022-3115(85)90168-0

Jambunathan, K., Shah, B. C., Hudson, J. L., & Hillier, A. C.

(2001). Scanning electrochemical microscopy of

hydrogen electro-oxidation. Rate constant measure-

ments and carbon monoxide poisoning on platinum.

Journal of Electroanalytical Chemistry,500, 279–289.

doi:10.1016/S0022-0728(00)00344-2

Jargin, S. V. (2011). Forest fires in the former Soviet Union:

No reasons for radiophobia. Journal of Environmental

Radioactivity, 102, 218–219. doi:10.1016/j.

jenvrad.2010.10.001

Jay, A. H., & Andrews, K. W. (1946). Note on oxide sys-

tems pertaining to steel-making furnace slags—FEO-

MNO, FEO-MGO, CAO-MNO, MGO-MNO. Journal of the

Iron and Steel Institute,152,15–18.

Jones, D. R., Paul, L., & Mitchell, N. G. (1999). Effects of

ameliorative measures on the radiocaesium transfer

to upland vegetation in the UK. Journal of

Environmental Radioactivity, 44, 55–69. doi:10.1016/

S0265-931X(98)00065-4

Jones, S. (2008). Windscale and Kyshtyrn: A double anni-

versary. Journal of Environmental Radioactivity,99,1–

6. doi:10.1016/j.jenvrad.2007.10.002

Kajan, I., Kärkelä, T., Tapper, U., Johansson, L.-S., Gouello,

M., Ramebäck, H., . . . Ekberg, C. (2017). Impact of Ag

and NOx compounds on the transport of ruthenium

in the primary circuit of nuclear power plant in a

severe accident. Annals of Nuclear Energy,100,9–19.

doi:10.1016/j.anucene.2016.10.008

Kajan, I., Lasseson, H., Persson, I., & Ekberg, C. (2016).

Interaction of ruthenium tetroxide with surfaces of

nuclear reactor containment building. Journal of

Nuclear Science and Technology,53, 1397–1408.

doi:10.1080/00223131.2015.1120245

Kajan, I., Tietze, S., & Ekberg, C. (2016). Interaction of

ruthenium tetroxide with iodine-covered surfaces of

materials in nuclear reactor containment building.

Journal of Nuclear Science and Technology,53, 1889–

1898. doi:10.1080/00223131.2016.1174627

Kaltofen, M., & Gundersen, A. (2017). Radioactively-hot

particles detected in dusts and soils from Northern

Japan by combination of gamma spectrometry,

autoradiography, and SEM/EDS analysis and implica-

tions in radiation risk assessment. Science of the

Total Environment,607–608, 1065–1072.

doi:10.1016/j.scitotenv.2017.07.091

Kamenik, J., Dulaiova, H., Sebesta, F., & St’antna, K.

(2013). Fast concentration of dissolved forms of

cesium radioisotopes from large seawater samples.

Journal of Radioanalytical and Nuclear Chemistry,

296, 841–846. doi:10.1007/s10967-012-2007-4

Kanda, Y., Miura, T., & Nakajima, H. (2005). Observation of

gaseous nitric acid production at a high-energy pro-

ton accelerator facility. Radiation Physics and

Chemistry,73, 213–217. doi:10.1016/j.

radphyschem.2004.08.009

Kanda, Y., Momose, T., & Taira, M. (1996). Characterization

of radiolytic products from air at a high-energy elec-

tronpositron storage ring. Radiation Physical Chemical,

48,49–54. doi:10.1016/0969-806X(95)00430-6

Karkela, T., Auvinen, A., Kekki, T., Kotiluoto, P., Lyyranen,

J., & Jokiniemi, J. (2015). Radiolytical oxidation of

gaseous iodine by beta radiation. Radiochimica Acta,

103, 719–728. doi:10.1515/ract-2015-2417

Karunakara, N., Ujwal, P., Yashodhara, I., Rao, C., Sudeep

Kumara, K., Dileep, B. N., & Ravi, P. M. (2013). Studies

on soil to grass transfer factor (F-v) and grass to milk

transfer coefficient (F-m) for cesium in Kaiga region.

Journal of Environmental Radioactivity,124, 101–112.

doi:10.1016/j.jenvrad.2013.03.008

Kendall, G. M., Muirhead, C. R., Darby, S. C., Doll, R., Arnold,

L., & O’Hagan, J. A. (2004). Epidemiological studies of

UK test veterans: I. General description. Journal of

Radiological Protection,24, 199–217. doi:10.1088/

0952-4746/24/3/001

Kim, W.-J., Kim, D., & Park, J. Y. (2013). Fabrication and

material issues for the application of sic composites

to LWR fuel cladding. Nuclear Engineering and

Technology,45, 565–572. doi:10.5516/

NET.07.2012.084

King, C. R., DiPetrillo, T. A., & Wazer, D. E. (2000). Optimal

radiotherapy for prostate cancer: Predictions for

conventional external beam, IMRT, and brachyther-

apy from radiobiologic models. International Journal

Radiation Oncology Biologic Physical, (46), 165–172.

doi:10.1016/S0360-3016(99)00406-X

Kitani, S., Noro, T., & Kohara, T. (1972). Removal of methyl

lodide by impregnated charcoals from flowing air

under humid condition. Journal of Nuclear Science

and Technology,9, 197–202. doi:10.1080/

18811248.1972.9734831

Kleszcz, K., & Mietelski, J. W. (2010). Ni-63 in Chernobyl

“ruthenium hot particles”and in forest soil samples.

Radiochimica Acta,98, 377–379. doi:10.1524/

ract.2010.1727

Klochkov, E. P., Risovanyi, V. D., Vaneev, Y. E., & Dorofeev,

A. N. (2002). Radiation characteristics of europium-

containing control rods in a SM-2 reactor after long-

term operation. Atomic Energy,93, 656–660.

doi:10.1023/A:1021096715382

Ko, M. K. W., Size, N. D., Scott, C., Rodriguez, J. M.,

Weisenstein, D. K., & Sander, S. P. (1998). Ozone

depletion potential of CH3Br. Journal of Geophysical

Research—Atmospheres, 103, 28187–28195.

doi:10.1029/98JD02537

Kogan, V., & Schumacher, P. M. (2008). Plutonium release

fractions from accidental fires. Nuclear Technology,

161, 190–202. doi:10.13182/NT08-A3922

Kolarik, Z., & Renard, E. V. (2005). Potential applications of

fission platinoids in industry. Platinum Metals Review,

49,79–90. doi:10.1595/147106705X35263

Kondo, K., Muramatsu, H., Kanda, Y., & Takahara, S.

(1984). Particle-size distribution of BE-7-aerosols

formed in high-energy accelerator tunnels.

International Journal Applications Radiation and

Isotopes,35, 939–944. doi:10.1016/0020-708X(84)

90206-0

Körblein, A. (2012). Response to “An unexpected mortal-

ity increase in the United States follows arrival of the

radioactive plume from Fukushima: Is there a corre-

lation?”International Journal of Health Services,42,

553–555. doi:10.2190/HS.42.3.k

Kumana, J. D., & Lemlich, R. (1974). Unlit cigarette or

cigar as a possible expedient gas mask.

Environmental Letters,6,19–23. doi:10.1080/

00139307409437341

Kutkov, V. A. (2000). Results of in vivo monitoring of the

witnesses of the Chernobyl accident. Radiation

Protection Dosimetry,89, 193–197. doi:10.1093/

oxfordjournals.rpd.a033063

Kuznetsova, I. S., Labutina, E. V., & Hunter, N. (2016).

Radiation risks of leukemia, lymphoma and multiple

myeloma incidence in the Mayak Cohort: 1948–2004.

PLOS ONE,11, e0162710. doi:10.1371/journal.

pone.0162710

Landeyro, P. A., & Buccafurni, A. (1991). Time-indepen-

dent neutronic analysis of the Chernobyl accident.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 93 of 100

Nuclear Science and Engineering,108, 126–149.

doi:10.13182/NSE91-A23813

Larin, A. E., Malyshevskii, V. S., & Fomin, G. V. (2014).

Altitude and latitude distribution of the production

rate of BE-7 in the earth’s atmosphere in the parma

model. Russian Physics Journal,57, 803–808.

doi:10.1007/s11182-014-0308-5

Larsen, R. J., Sanderson, C. G., Lee, H.-N., Decker, K. M., &

Beck, H. L. (1994). Fission-products detected in

Alaska following the Tomsk-7 accident. Journal of

Environmental Radioactivity,23, 205–209.

doi:10.1016/0265-931X(94)90061-2

Lasithiotakis, M., Marsden, B. J., & Marrow, T. J. (2013).

Annealing of ion irradiation damage in nuclear gra-

phite. Journal of Nuclear Materials,427,95–109.

doi:10.1016/j.jnucmat.2012.04.013

Lea, D. E., & Catheside, D. G. (1942). The mechanism of

the induction by radiation of chromosome aberra-

tions inTradescantia. Journal of Genetics, 44, 216–

254. doi:10.1007/BF02982830

Lebaron-Facobs, L., Gaillard-Lecanu, E., Briot, F.,

Distinguin, S., Boisson, P., Exmelin, L., . . . Fottorino, R.

(2007). Hair dosimetry following neutron irradiation.

Health Physics,92, S98–S104. doi:10.1097/01.

HP.0000256282.71542.19

Lee, M. H., & Clark, S. B. (2005). Activities of Pu and Am

isotopes and isotopic ratios in a soil contaminated by

weapons-grade plutonium. Environmental Science &

Technology,39, 5512–5516. doi:10.1021/es0486115

Legg, C. J., Maltby, E., & Proctor, M. C. F. (1992). The

ecology of severe moorland fire on the North York

moors—seed distribution and seedling establish-

ment of calluna-vulgaris. Journal of Ecology,80, 737–

752. doi:10.2307/2260863

Leggett, R. W. (1993). An age-specific kinetic-model of

lead metabolism in humans. Environmental Health

Perspectives,101,598–616. doi:10.1289/

ehp.93101598

Leibowitz, L., & Blomquist, R. A. (1991). Thermodynamics

and phase-equilibria of the iron uranium system.

Journal of Nuclear Materials,184,47–52. doi:10.1016/

0022-3115(91)90531-B

Lexa, D., & Dauke, M. (2009). Thermal and structural

properties of low-fluence irradiated graphite. Journal

of Nuclear Materials,384, 236–244. doi:10.1016/j.

jnucmat.2008.11.013

Lexa, D., & Kropf, A. J. (2006). Thermal, structural, and

radiological properties of irradiated graphite from

the ASTRA research reactor—implications for dispo-

sal. Journal of Nuclear Materials,348, 122–132.

doi:10.1016/j.jnucmat.2005.09.010

Li, S. W., Chen, J., & Wan, J. C. (2012). Reduction and

removal of neptunium from synthetic high level

liquid waste by TRPO process. Journal of

Radioanalytical and Nuclear Chemistry,292, 697–704.

doi:10.1007/s10967-011-1480-5

Li, W., Duan, W., Sun, T., Liu, C., Wang, J., & Chen, J. (2017).

Denitration of simulated high-level liquid waste by for-

mic acid for the connection of PUREX process with TRPO

process. Journal of Radioanalytical and Nuclear

Chemistry,314, 221–229. doi:10.1007/s10967-017-

5357-0

Lin, C. C., & Chao, J. H. (2006). Radiochemical analysis in

fuel integrity evaluation. Nuclear Technology,160,

244–250. doi:10.13182/NT07-A3896

Lin, C. C., & Skarpelos, J. M. (1997). Monitoring of fission

product release in a boiling water reactor. Journal of

Radioanalytical and Nuclear Chemistry,220, 173–181.

doi:10.1007/BF02034852

Liu, R. Q., Zou, Q., Zu, J. H., Wei, Y. Z., Ding, Y. Q., & Zhao, Y.

P. (2017). Feasibility studies on the selective

separation of fission palladium(II) by isoHex-BTP/

SiO2-P adsorbent from HLLW. Journal of Nuclear

Science and Technology,54, 899–907. doi:10.1080/

00223131.2017.1323687

Lloyd, D. C., Edwards, A. A., Fitzsimons, E. J., Evans, C. D.,

Railton, R., Jeffrey, P., . . . Sumitomo, H. (1994). Death

of classified worker probably caused by overexposure

to gamma-radiation. Occupational and

Environmental Medicine,51, 713–718. doi:10.1136/

oem.51.10.713

Loos-Neskovic, C., Ayrault, S., Badillo, V., Jimenez, B.,

Garnier, E., Fedoroff, M., . . . Merinov, B. (2004).

Structure of copper-potassium hexacyanoferrate(II)

and sorption mechanisms of cesium. Journal of Solid

State Chemistry,177, 1817–1828. doi:10.1016/j.

jssc.2004.01.018

Lopresti, V., Conradson, S. D., & Clark, D. L. (2007). XANES

identification of plutonium speciation in RFETS sam-

ples. Journal of Alloys and Compounds,444–445,

540–543. doi:10.1016/j.jallcom.2006.10.101

Lord, B. I., Woolford, L. B., Wang, L., Stones, V. A.,

McDonald, D., Lorimore, S. A., . . . Scott, D. (1998).

Tumour induction by methyl nitroso-urea precon-

ceptional paternal contamination with plutonium-

239. British Journal of Cancer, 78, 301–311.

doi:10.1038/bjc.1998.491

Lovejoy, E. R., Wang, N. S., & Howard, C. J. (1987). Kinetic-

studies of the reactions of HSO with NO

, NO, and O

Journal Physical Chemical,91, 5749–5755.

doi:10.1021/j100306a046

Lovelock, J. E., Maggs, R. J., & Wade, R. J. (1973).

Halogenated hydrocarbons in and over the Atlantic.

Nature,241, 194–196. doi:10.1038/241194a0

Lujaniene, G., Šapolaite, J., Remeikis, V., Lujanas, V.,

Jermolajev, A., & Aninkevičius, V. (2006). Cesium,

americium and plutonium isotopes in ground level air

of vilnius. Czechoslovak Journal of Physics,56, D55–

D61. doi:10.1007/s10582-006-1077-3

Lundberg, D., & Persson, I. (2016). The size of actinoid(III)

ions—structural analysis vs. common misinterpreta-

tions. Coordination Chemistry Reviews,318, 131–134.

doi:10.1016/j.ccr.2016.04.003

Luther, T. A., Herbst, R. S., Peterman, D. R., Tillotson, R. D.,

Garn, T. G., Babain, V. A., . .. Antono, N. G. (2006). Some

aspects of fundamental chemistry of the Universal

Extraction (UNEX) process for the simultaneous

separation of major radionuclides (cesium, strontium,

actinides, and lanthanides) from radioactive wastes.

Journal of Radioanaytical and Nuclear Chemistry,267,

603–613. doi:10.1007/s10967-006-0114-9

Macdonald, H. F., Ballard, P. J., Thompson, I. M. G.,

Goldfinch, E. P., & Orchard, H. C. (1977). Development

and current status of emergency monitoring proce-

dures at CEGB nuclear-power stations. Journal of the

British Nuclear Energy Society,16, 177–186.

Megaw, W.J. & May, F.G., (1962). Behaviour of iodine

released in reactor containers. Journal of nuclear

energy parts a and b-reactor science and technology,

16, 427, doi:10.1016/0368-3230(62)90195-7

Malecki, G., & Ratuszna, A. (1999). Crystal structure of

cyanometallates Me-3[Co(CN)(6)](2) and KMe[Fe(CN)

(6)] with Me = Mn

,Ni

,Cu

.Powder Diffraction,14,

25–30. doi:10.1017/S0885715600010265

Malizia, L. A., Poggi, J.-F., Rossi, C. R., Bellecci, C., & Gaudio, P.

(2016). A review of dangerous dust in fusion reactors:

From its creation to its resuspension in case of LOCA

and LOVA. Energies,(9),578.doi:10.3390/en9080578

Mangano, J. J., & Sherman, J. D. (2012). An unexpected

mortality increase in the United States follows arrival

of the radioactive plume from Fukushima: Is there a

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 94 of 100

correlation? International Journal of Health Services,

42,47–64. doi:10.2190/HS.42.1.f

Marchetti, A. A., & Straume, T. (1996). A search for neu-

tron reactions that may be useful for Hiroshima dose

reconstruction. Applied Radiation and Isotopes,47,

97–103. doi:10.1016/0969-8043(95)00240-5

Marinelli, L. D., Norris, W. P., Gustafson, P. F., & Speckman,

T. W. (1953). Transport of radium sulfate from the

lung and its elimination from the human body fol-

lowing single accidental exposures. Radiology,61,

903–915. doi:10.1148/61.6.903

Mazzocchi, C., Janas, Z., Bączyk, P., Fynbo, H. O. U., &

Köster, U. (2012). Precision half-life measurement of

Be-7 implanted in different materials. Acta Physica

Polonica B,43, 279–284. doi:10.5506/

APhysPolB.43.279

McCarthy, J. F., Sanford, W. E., & Stafford, P. L. (1998).

Lanthanide field tracers demonstrate enhanced

transport of transuranic radionuclides by natural

organic matter. Environmental Science and

Technology,32, 3901–3906. doi:10.1021/es971004f

McCurry, J. (2017, March 10). Fukushima evacuees face

‘forced’return as subsidies withdrawn. The Guardian.

Retrieved from https://www.theguardian.com/world/

2017/mar/10/japan-fukushima-nuclear-disaster-evac

uees-forced-return-home-radiation

McLaughlin, T. P., Monahan, S. P., Pruvost, N. I., Frolov, V.

V., Ryazanov, B. G., & Sviridov, V. I. (2000). A review of

criticality accidents 2000 review. Los Alamos, NM: Los

Alamos National Laboratory.

McMurray, H. N. (1993). Uniform colloids of ruthenium

dioxide hydrate evolved by the surface-catalyzed

reduction of ruthenium tetroxide. Journal Physical

Chemical,97, 8039–8045. doi:10.1021/j100132a038

Medvedev, Z. A. (1976). Two decades of dissidence. New

Scientist,72(1025), 264–267.

Meijer, W. O. J. (1955). Synthesis, structures, and proper-

ties of platinum metal tellurides. American

Mineralogist,40, 646–657.

Melo, D. R., Lipsztein, J. L., Oliveira, C. A. N., Lundgren, D.

L., Muggenburg, B. A., & Guilmette, R. A. (1997). A

biokinetic model for Cs-137. Health Physics,73, 320–

332. doi:10.1097/00004032-199708000-00004

Métivier, H., & Waight, P. (2002). Chernobyl: Assessment of

radiological and health impacts 2002 update of

Chernobyl: Ten years on. Boulogne-Billancourt:

Nuclear Energy Agency OCED (Organisation for

Economic Co-operation and Development).

Miller, B., Kane, P. O., Robinson, D. B., & Whittingham, P. J.

(1978). Determination of a 24-hour time-weighted

average value of environmental vinyl-chloride

monomer concentration by charcoal adsorption fol-

lowed by gas-chromatography. Analyst,103, 1165–

1172. doi:10.1039/an9780301165

Milyutin, V. V., Gelis, V. M., Dzekun, E. G., & Malykh, Y. A.

(1995). Sorption technology for removal of cesium-

137 from solutions of spent nuclear-fuel reproces-

sing. Radiochemistry, 37, 85–87.

Mitchell, E. W., & Taylor, M. R. (1965). Mechanism of

stored-energy release at 200degrees C in electron-

irradiated graphite. Nature, 208, 638–641.

doi:10.1038/208638a0

Molchanova, I., Mikhailovskaya, L., Antonov, K.,

Pozolotina, V., & Antonova, E. (2014). Current

assessment of integrated content of long-lived

radionuclides in soils of the head part of the East Ural

Radioactive Trace. Journal of Environmental

Radioactivity,138, 238–248. doi:10.1016/j.

jenvrad.2014.09.004

Monroe, K. R., Murphy, S. P., Kolonel, L. N., & Pike, M. C.

(2007). Prospective study of grapefruit intake and risk

of breast cancer in postmenopausal women: The

Multiethnic Cohort Study. British Journal of Cancer,

97, 440–445. doi:10.1038/sj.bjc.6603880

Montero, M. P. R., & Sánchez, A. M. (2001). Activity of

Pu239+240 and Pu-238 in atmospheric deposits.

Applied Radiation and Isotopes,55,97–102.

doi:10.1016/S0969-8043(00)00365-1

Moore, F. L. (1960). Liquid-liquid extraction of uranium

and plutonium from acetate solution with triiso-

octylamine—separation from thorium and fission

products. Anayltical Chemistry,32, 1075–1079.

doi:10.1021/ac60165a007

Moskvin, A. I. (1969). On the complex formation of acti-

nides with acid anions in aqueous solutions.

Radiokhimiya,11, 458.

Mouly, S., Lloret-Linares, C., Sellier, P. O., Sene, D., &

Bergmann, J. F. (2017). Is the clinical relevance of

drug-food and drug-herb interactions limited to

grapefruit juice and Saint-John’s Wort?

Pharmacological Research, (118), 82–92. doi:10.1016/

j.phrs.2016.09.038

Moyer, M. (2011). Retrieved October 26, 2017, from

https://blogs.scientificamerican.com/observations/

researchers-trumpet-another-flawed-fukushima-

death-study/

Mraz, F. R. (1959). Influence of dietary potassium and

sodium on cesium-134 and potassium-42 excretion

in sheep. Journal of Nutrition,68, 655–662.

doi:10.1093/jn/68.4.655

Mu, X., Löfroth, P.-O., Karlsson, M., & Zackrisson, B. (2003).

The effect of fraction time in intensity modulated

radiotherapy: Theoretical and experimental evalua-

tion of an optimisation problem. Radiotherapy and

Oncology,68, 181–187. doi:10.1016/S0167-8140(03)

00165-8

Muirhead, C. R., Kendall, G. M., Darby, S. C., Doll, R.,

Haylock, R. G. E., O’Hagan, J. A., . . . Hunter, N. (2004).

Epidemiological studies of UK test veterans: II.

Mortality and cancer incidence. Journal of

Radiological Protection, 24, 219–241. doi:10.1088/

0952-4746/24/3/002

Murray, R. L. (1988, August). The etymology of “scram”.

Nuclear News, pp. 106–107.

Nakanishi, H., Mori, A., Takeda, K., Tanaka, H., Kobayashi,

N., Tanoi, K., . . . Mori, S. (2015). Discovery of radio-

active silver (

110m

Ag) in spiders and other fauna in

the terrestrial environment after the meltdown of

Fukushima Dai-ichi nuclear power plant Proceedings

of the Japan Academy Series B: Physical and Biological

Sciences,91, 160–174.

Nakano, T., Tani, K., Kim, E., Kurihara, O., Sakai, K., &

Akashi, M. (2016). Three-year retention of radioactive

caesium in the body of tepco workers involved in the

Fukushima Daiichi nuclear power station accident.

Radiation Protection Dosimetry,170, 315–317.

doi:10.1093/rpd/ncw036

Nedunchezhian, K., Aswath, N., Thiruppathy, M., &

Thirugnanamurthy, S. (2016). Boron neutron capture

therapy—a literature review. Journal of Clinical and

Diagnostic Research,10, ZE1–ZE4.

Neuschütz, D. S., Quade, U., Meier-Kortwig, J., Holappa, L.,

Hämäläinen, M., Lozano, M. A. H., & Bonany, M. J. G.

(2005). Inadvertent melting of radioactive sources in

BOF or EAF: Distribution of nuclides, monitoring, pre-

vention. ISIJ International,45, 288–295. doi:10.2355/

isijinternational.45.288

Newton, D. (1966). A case of accidental inhalation of

actinium-227. Health Physics,12, 1129–1138.

doi:10.1097/00004032-196608000-00015

Nie, B., Ni, M., & Wei, S. (2017). Individual dose due to

radioactivity accidental release from fusion reactor.

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 95 of 100

Journal of Hazardous Materials,327, 135–143.

doi:10.1016/j.jhazmat.2016.12.018

Nielsen, C. E., Wilson, D. A., Brooks, A. L., McCord, S. L.,

Dagle, G. E., James, A. C., . . . Morga, W. F. (2012).

Microdistribution and long-term retention of Pu-239

(NO3)(4) in the respiratory tracts of an acutely

exposed plutonium worker and experimental beagle

dogs. Cancer Research,72, 5529–5536. doi:10.1158/

0008-5472.CAN-12-1824

Ning,P.,Qiu,J.,Wang,X.Q.,Liu,W.,&Chen,W.

(2013). Metal loaded zeolite adsorbents for

hydrogen cyanide removal. Journal of

Environmental Sciences,25, 808–814. doi:10.1016/

S1001-0742(12)60138-7

Noguchi, H., & Murata, M. (1988). Physicochemical spe-

ciation of airborne I-131 in japan from Chernobyl.

Journal of Environmental Radioactivity,7,65–74.

doi:10.1016/0265-931X(88)90042-2

Nomura, H., Maeseto, T., & Osako, M. (2017). Behavior of

radioactive cesium during incineration of radioac-

tively contaminated wastes from decontamination

activities in Fukushima. Journal of Environmental

Radioactivity,178, 290–296.

Nomura, S., Blangiardo, M., Tsubokura, M., Nishikawa, Y.,

Gilmour, S., Kami, M., & Hodgson, S. (2016). Post-

nuclear disaster evacuation and survival amongst

elderly people in Fukushima: A comparative analysis

between evacuees and non-evacuees. Preventative

Medicine, 82, 77–82. doi:10.1016/j.

ypmed.2015.11.014

Nomura, T. (1982). Parental exposure to X-rays and che-

micals induces heritable tumors and anomalies in

mice. Nature,296, 575–577. doi:10.1038/296575a0

Norman, C. (1983). The Kyshtym mystery (CONTD).

Science,221, 138. doi:10.1126/science.221.4606.138

Norman, E. B., Rech, G. A., Browne, E., Larimer, R.-M.,

Dragowsky, M. R., & Chan, Y. D. (2001). Influence of

physical and chemical environments on the decay

rates of Be-7 and K-40. Physics Letters B,519,15–22.

doi:10.1016/S0370-2693(01)01097-8

Oak Ridge. (1999). Retrieved September 30, 2017, from

http://www.orau.org/ptp/collection/dosimeters/dosi

meters.htm

Odintsov, A. A., Khan, V. E., Krasnov, V. A., Pazukhin, E. M.,

& Shcherbin, V. N. (2009). Transuranium elements in

liquid radioactive wastes from the Shelter.

Radiochemistry,51, 383–389. doi:10.1134/

S1066362209040109

Ogorodnikov, B. I., Budyka, A. K., Khan, V. E., Pazukhin, E.

M., Koval’chuk, V. P., & Krasnov, V. A. (2009).

220

Rn as

an additional factor of radiation hazard in the

Shelter. Radiochemistry,51, 390–399. doi:10.1134/

S1066362209040110

Olson, M. (2011). Atomic radiation is more harmful to

women. Nuclear Information and Resource Service

Briefing Paper. Retrieved from https://www.nirs.org/

wp-content/uploads/2017/02/corrected-radiationwo

menfinal.pdf

Papastefanou, C., Manolopoulou, M., & Charalambous, S.

(1988). Silver-110m and Sb-125 in Chernobyl fallout.

Science of the Total Environment,72,81–85.

doi:10.1016/0048-9697(88)90008-3

Parajuli, D., Tanaka, H., Hakuta, Y., Minami, K., Fukuda, S.,

Umeoka, K., . . . Kawamoto, T. (2013). Dealing with

the aftermath of Fukushima Daiichi nuclear accident:

Decontamination of radioactive cesium enriched ash.

Environmental Science and Technology,47, 3800–

3806. doi:10.1021/es303467n

Paramonova, V. I., & Kalychev, V. B. (1966). Some addi-

tional notes to the theory of method of relative

absorption using U(VI) in acetate-nitrate solutions as

an example. Radiokhimiya,8, 304.

Pedersen-Bjergaard, J., Philip, P., Mortensen, B. T., Ersb, J.,

ll, Jensen, G., Panduro, J., & Thomsenen, M. (1981).

Acute nonlymphocytic leukemia, preleukemia, and

acute myeloproliferative syndrome secondary to

treatment of other malignant diseases. Clinical and

cytogenetic characteristics and results of in vitro

culture of bone marrow and HLA typing. Blood,57,

712–723.

Perricone, A., & Noël, H. (2002). Crystal structure and

magnetic properties of the binary uranium-nickel

alloy UNi4. Intermetallics,10, 519–521. doi:10.1016/

S0966-9795(02)00015-8

Perricone, A., Potel, M., & Noël, H. (2002). Crystal structure

and magnetic properties of the binary uranium-

nickel alloy U11Ni16. Journal of Alloys and

Compounds,340,39–42. doi:10.1016/S0925-8388

(02)00009-9

Ph Hubert, F., Gaye, P. J., Medina, B., & Pravikoff, M. S.

(2009). Radioactivity measurements applied to the

dating and authentication of old wines. Comptes

Rendus Physique,10, 622–629. doi:10.1016/j.

crhy.2009.08.007

Pinder, J. E., III, Hinton, T. G., Taylor, B. E., & Whicker, F. W.

(2011). Cesium accumulation by aquatic organisms

at different trophic levels following an experimental

release into a small reservoir. Journal of

Environmental Radioactivity,102, 283–293.

doi:10.1016/j.jenvrad.2010.12.003

Platonov, P. A., Burlakov, E. V., Chugunov, O. K., Dostov, A.

I., Alekseev, V. M., & Smorodkin, E. I. (2003).

Computational-experimental investigation of the

Wigner energy and the physical properties of plunger

graphite in the safety and control system of an RBMK

reactor. Atomic Energy,94, 225–237. doi:10.1023/

A:1024737702092

Porfiriev, B. N. (1996). Environmental aftermath of the

radiation accident at Tomsk-7. Environmental

Management,20,25–33. doi:10.1007/PL00006699

Ramirez, N., Cuadras, A., Rovira, E., Borrull, F., & Marce, R.

M. (2010). Comparative study of solvent extraction

and thermal desorption methods for determining a

wide range of volatile organic compounds in ambient

air. Talanta,82, 719–727. doi:10.1016/j.

talanta.2010.05.038

Renaud, P., & Gonze, M.-A. (2014). Lessons from the

Fukushima and Chernobyl accidents concerning the

Cs-137 contamination of orchard fresh fruits.

Radioprotection,49, 169–175. doi:10.1051/radiopro/

2014004

Resende, S. M. (2007). The atmospheric oxidation of the

HS radical: Reaction with NO

.Journal Atmos

Chemical,56,21–32. doi:10.1007/s10874-006-9040-z

Reyerson, L. H., & Cameron, A. E. (1936). The sorption of

bromine and iodine by activated charcoal. Journal

Physical Chemical,40, 233–237. doi:10.1021/

j150371a009

Richardson, D., Sugiyama, H., Nishi, N., Sakata, R., Shimizu,

Y., Grant, E. J., . . . Kasagi, F. (2009). Ionizing radiation

and leukemia mortality among Japanese Atomic

Bomb Survivors, 1950–2000. Radiation Research,172,

368–382. doi:10.1667/RR1801.1

Robison, W. L., Brown, P. H., Stone, E. L., Hamilton, T. F.,

Conrado, C. L., & Kehl, S. (2009). Distribution and

ratios of Cs-137 and K in control and K-treated

coconut trees at Bikini Island where nuclear test

fallout occurred: Effects and implications. Journal of

Environmental Radioactivity,100,76–83. doi:10.1016/

j.jenvrad.2008.10.016

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 96 of 100

Robison, W. L., Conrado, C. L., Bogen, K. T., & Stoker, A. C.

(2003). The effective and environmental half-life of

Cs-137 at Coral Islands at the former US nuclear test

site. Journal of Environmental Radioactivity,69, 207–

223. doi:10.1016/S0265-931X(03)00080-8

Romanchuk, A. Y., Kalmykov, S. N., Egorov, A. V.,

Zubavichus, Y. V., Shiryaev, A. A., Batuk, O. N., . . .

Presnyakov, I. A. (2013). Formation of crystalline

PuO2+x center dot nH(2)O nanoparticles upon sorp-

tion of Pu(V,VI) onto hematite. Geochimica et

Cosmochimica Acta,121,29–40. doi:10.1016/j.

gca.2013.07.016

RPPI. (2006). Retrieved from https://web.archive.org/web/

20131015024743/http://www.rpii.ie/Site/Media/

Press-Releases/RTE-s-docudrama-scenario-could-

not-happen-accordin.aspx

Rudenko, L. I., & Khan, V. E. (2005). Membrane methods

for treating liquid radioactive wastes from the shelter

to remove transuranic elements. Radiochemistry,47,

89–92. doi:10.1007/s11137-005-0054-1

Rudenko, L. I., & Khan, V. E. (2005a). Contribution of

radionuclides associated with microparticles to their

migration from the shelter and its service area to

groundwater. Radiochemistry,47,93–95.

doi:10.1007/s11137-005-0055-0

Russell, W. L. (1957). Shortening of life in the offspring of

male mice exposed to neutron radiation from an

atomic bomb. Proceedings of the National Academy

of Sciences of the United States of America,43, 324–

329. doi:10.1073/pnas.43.4.324

Saccomanno, G., Huth, G. C., Auerbach, O., & Kuschner, M.

(1988). Relationship of radioactive radon daughters

and cigarette-smoking in the genesis of lung-cancer

in uranium miners. Cancer,62, 1402–1408.

doi:10.1002/(ISSN)1097-0142

Sahoo, S. K., Kavasi, N., Sorimchi, A., Arae, H., Tokonami,

S., Mietelski, J. W., . .. Yoshida, S. (2016). Strontium-90

activity concentration in soil samples from the

exclusion zone of the Fukushima Daiichi nuclear

power plant. Scientific Reports,6, 23925. doi:10.1038/

srep23925

Sakai, E. (1984). Performance of a nuclear-reactor cover-

gas monitor using charcoal—GE gamma-ray spec-

trometer combination. IEEE Transactions on Nuclear

Science,NS-31,757–760. doi:10.1109/

TNS.1984.4333361

Salminen, S., Paatero, J., Jaakkola, T., & Lehto, J. (2005).

Americium and curium deposition in Finland from the

Chernobyl accident. Radiochimica Acta,93, 771–779.

doi:10.1524/ract.2005.93.12.771

Sanap, K. K., Varma, S., Waghmode, S. B., & Bharadwaj, S.

R. (2015). Wire gauze and cordierite supported noble

metal catalysts for passive autocatalytic recombiner.

Nuclear Engineering and Design,294, 226–232.

doi:10.1016/j.nucengdes.2015.09.010

Sánchez, A. M., de la Torre Pérez, J., Sánchez, A. B. R., &

Correa, F. L. N. (2013). Additional contamination

when radon is in excess. Applied Radiation and

Isotopes,81, 212–215. doi:10.1016/j.

apradiso.2013.03.004

Sandalls, F. J., Segal, M. G., & Victorova, N. (1993). Hot

particles from Chernobyl—a review. Journal of

Environmental Radioactivity,18,5–22. doi:10.1016/

0265-931X(93)90063-D

Sanders, C. L., & Adee, R. R. (1968). Phagocytosis of

inhaled plutonium oxide-239Pu particles by pulmon-

ary macrophages. Science,162(3856), 918–920.

doi:10.1126/science.162.3856.918

Sanzharova, N. I., Fesenko, S. V., Alexakhin, R. M.,

Anisimov, V. S., Kuznetsov, V. K., & Chernyayeva, L. G.

(1994). Changes in the forms of 137Cs and its

availability for plants as dependent on properties of

fallout after the Chernobyl nuclear power plant acci-

dent. Science of the Total Environment,154,9–22.

doi:10.1016/0048-9697(94)90609-2

Sappok, M. (1991). Recycling of metallic materials from the

dismantlingof nuclear-plants.Kerntechnik,56,376–378.

Schneider, U., Stipper, A., & Besserer, J. (2010). Dose-

response relationship for lung cancer induction at

radiotherapy dose. Z Medica Physical,20, 206–214.

doi:10.1016/j.zemedi.2010.03.008

Schneider, U., Sumila, M., Robotka, J., Gruber, G., Mack, A.,&

Besserer, J. (2011). Dose-response relationship for

breast cancer induction at radiotherapy dose. Radiation

Oncology,6(67), 1–7. doi:10.1186/1748-717X-6-67

Schubert, W., Cullberg, G., Edgar, B., & Hedner, T. (1994).

Inhibition of 17-beta-estradiol metabolism by grape-

fruit juice in ovariectomized women. Maturitas,20,

155–163. doi:10.1016/0378-5122(94)90012-4

Schweiger, M., Seidel, S. R., Arif, A. M., & Stang, P. J. (2002).

Solution and solid state studies of a triangle-square

equilibrium: Anion-induced selective crystallization in

supramolecular self-assembly. Inorganic Chemistry,

41, 2556–2559. doi:10.1021/ic0112692

Selby, P. B., Earhart, V. S., & Raymer, G. D. (2005). The

influence of dominant lethal mutations on litter size

and body weight and the consequent impact on

transgenerational carcinogenesis. Mutation Research,

578, 382–394. doi:10.1016/j.mrfmmm.2005.06.025

Selby, P. B., & Priest, N. D. (2005). First-generation off-

spring of male mice exposed to Pu-239-citrate show

no evidence of leukaemia or life shortening.

International Journal of Radiation Biology,81, 273–

290. doi:10.1080/09553000500140480

Serezhkina, L. B., Vologzhanina, A. V., Klepov, V. V., &

Serezhkin, V. N. (2011). СИНТЕЗ И

РЕНТГЕНОСТРУКТУРНОЕ ИССЛЕДОВАНИЕ

(CS

0.5

0.25

)[UO

(CH

COO)

]ИBA

0.5

[UO

(CH

COO)

]

[Synthesis and X-ray structural study of (CS

0.5

0.25

)

[UO

(CH

COO)

] and BA

0.5

[UO

(CH

COO)

]].

Kristallografiya,56, 290.

Serezhkina, L. V., Vologzhanina, A. V., Klepov, V. V., &

Serezhkin, V. N. (2010). КРИСТАЛЛИЧЕСКАЯ

СТРУКТУРА R[UO

(CH

COO)

](R= NH, K

ИЛИ CS

)

[Crystalline structure of R [UO

(CH

COO)

](R= NH,

or CS

)]. Kristallografiya,55, 822.

Serrano-Purroy, D., Christiansen, B., Glatz, J.-P., Malmbeck,

R., & Modolo, G. (2005). Towards a DIAMEX process

using high active concentrate. Production of genuine

solutions. Radiochimica Acta,93, 357–361.

doi:10.1524/ract.93.6.357.65645

Shann, S. H., & Olander, D. R. (1983). Stress-corrosion

cracking of zircaloy by cadmium, iodine, and metal

iodides. Journal of Nuclear Materials,113, 234–248.

doi:10.1016/0022-3115(83)90148-4

Sheil, A. E., Botzem, W., & Johnston, C. K. (1999).

Decommissioning of windscale pile 1.WM’99

Conference. Tucson, Arizona. Retrieved from http://

www.wmsym.org/archives/1999/02/2-1.pdf

Shiba, K., Hanada, M., & Yajima, S. (1969). Chemical state

of fission tellurium released from irradiated UO2 and

UO2-graphite mixtures. Journal of Nuclear Science

and Technology,6, 333–337. doi:10.1080/

18811248.1969.9732897

Shih, T.-S., Liu, J.-B., & Wei, P.-S. (2007). Oxide films on

magnesium and magnesium alloys. Materials

Chemistry and Physics,104, 497–504. doi:10.1016/j.

matchemphys.2007.04.010

Shikata, E., & Amano, H. (1973). Dry-distillation of iodine-

131 from several tellurium compounds. Journal of

Nuclear Science and Technology, (10), 80–88.

doi:10.1080/18811248.1973.9735382

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 97 of 100

Shilnikova, N. S., Preston, D. L., Ron, E., Gilbert, E. S.,

Vassilenko, E. K., Romanov, S. A., . . . Koshurnikova, N.

A. (2003). Cancer mortality risk among workers at the

Mayak nuclear complex. Radiation Research,159,

787–798. doi:10.1667/0033-7587(2003)159[0787:

CMRAWA]2.0.CO;2

Shiota, K., Takaoka, M., Fujimori, T., Oshita, K., & Terada, Y.

(2015). Cesium speciation in dust from municipal

solid waste and sewage sludge incineration by syn-

chrotron radiation micro-X-ray analysis. Analytical

Chemistry,87, 11249–11254. doi:10.1021/acs.

analchem.5b03298

Skarlou, V., Nobeli, C., Anoussis, J., Haidouti, C., &

Papanicolaou, E. (1999). Transfer factors of Cs-134

for olive and orange trees grown on different soils.

Journal of Environmental Radioactivity,45, 139–147.

doi:10.1016/S0265-931X(98)00098-8

Sloter, E., Nemec, M., Stump, D., Holson, J., Kirkpatrick, D.,

Gargas, M., & Kinzell, J. (2009). Methyl iodide-induced

fetal hypothyroidism implicated in late-stage fetal

death in rabbits. Inhalation Toxicology,21, 462–479.

doi:10.1080/08958370802596942

Smallman, C. (1981). Biology for you book one (pp. 142).

London: Hutchinson.

Son, Y.-S., Jung, I.-H., Lee, S.-J., Koutrakis, P., & Kim, J.-C.

(2015). Decomposition of sulfur compounds by radi-

olysis: II. By-products and mechanisms. Chemical

Engineering Journal,269,27–34. doi:10.1016/j.

cej.2015.01.079

Soran, D. M., & Stillman, D. B. (1982). An analysis of the

alleged Kyshtym disaster, LA-9217-MS. Los Alamos:

Los Alamos National Lab.

Spalding, J. F., Brooks, M. R., & Tietjen, G. L. (1969).

Lifetime body weights and mortality distributions of

mice with 10 generations to 35 generations of

ancestral X-ray exposure. Genetics,63, 897–906.

Spencer, E. A., Key, T. J., Appleby, P. N., van Gils, C. H.,

Olsen, A., Tjønneland, A., . . . Riboli, E. (2009).

Prospective study of the association between grape-

fruit intake and risk of breast cancer in the European

Prospective Investigation into Cancer and Nutrition

(EPIC). Cancer Causes & Control,20,803–809.

doi:10.1007/s10552-009-9310-6

SRP. (2011). A practical guide to decommissioning for the

medical. Industrial or Research Small User, can be

downloaded from. Retrieved from https://srp-uk.org/

resources/practical-advice

Stewart, F. A., Akleyev, A. V., Hauer-Jensen,M., Hendry, J. H.,

Kleiman, N. J., MacVittie, T. J., .. . Wallace, W. H. (2012).

ICRP statement on tissue reactions/early and late

effects of radiation in normal tissues and organs—

threshold doses for tissue reactions in a radiation pro-

tection context. Annals of the ICRP,41,118.(ICRP

Publication).

Stewart, N. G., Crooks, R. N., & Fisher, E. M. R. (1961).

Measurements of the Radioactivity of the Cloud from

the Accident at Windscale: Data submitted to the I.G.

Y. United Kingdom Atomic Energy Authority, AERE-M,

857, 1961.

Swider-Lyons, K. E., Love, C. T., & Rolison, D. R. (2005).

Selective vapor deposition of hydrous RuO

thin films.

Journal of the Electrochemical Society,152, C158–

C162. doi:10.1149/1.1859713

Takahashi, T., Watanabe, H., Dohi, K., & Ito, A. (1992). CF-

252 relative biological effectiveness and inheritable

effect of fission neutrons in mouse-liver tumorigen-

esis. Cancer Research,52, 1948–1953.

Takewaki, I. (2011). Preliminary report of the 2011 off

the Pacific coast of Tohoku Earthquake. University

Science A (Applied Physical & Engineering),12,

327–334.

Tassaneeyakul, W., Guo, L.-Q., Fukuda, K., Ohta, T., &

Yamazoe, Y. (2000). Inhibition selectivity of grape-

fruit juice components on human cytochromes P450.

Archives of Biochemistry and Biophysics,378, 356–

363. doi:10.1006/abbi.2000.1835

Taylor, N. P., & Raskob, W. (2007). Updated accident

consequence analyses for ITER at Cadarache. Fusion

Science and Technology, 52, 359–366. doi:10.13182/

FST07-A1514

Telling, R. H., & Heggie, M. I. (2007). Radiation defects in

graphite. Philosophical Magazine,87, 4797–4846.

doi:10.1080/14786430701210023

Thouless, R. H. (1953). Straight and crooked thinking.

London: Pan Books.

Tinganelli, W., Durante, M., Hirayama, R., Krämer, M., Maier,

A., Kraft-Weyrather, W., .. . Scifoni, E. (2015). Kill-paint-

ing of hypoxic tumours in charged particle therapy.

Scientific Reports,5, 17016. doi:10.1038/srep17016

Torgov, V. G., Tatatchuk, V. V., Druzhinina, I. A., Korda, T.

M., & Renard, E. V. (2000). Possibility of a high degree

of removal of silver from fission palladium by petro-

leum sulfides. Atomic Energy,88, 373–377.

doi:10.1007/BF02680532

Torgov, V. G., Tatatchuk, V. V., Druzhinina, I. A., Korda, T.

M., Tatatchuk, A. N., & Renard, E. V. (1994).

Justification of the choice of an extraction system on

the basis of petroleum sulfides for extracting frag-

ment palladium. Atomic Energy, (76), 442–448.

doi:10.1007/BF02408108

Tuma, D. (2000). suffolk study to target rare cancer clus-

ter. Daily News. Retrieved from http://www.nydaily

news.com/archives/boroughs/suffolk-study-target-

rare-cancer-cluster-article-1.884577

Ulrich, K. (2017). Unequal impact. Edited A. Kashiwagi and

K. Suzuki. Tokyo: Greenpeace. http://www.green

peace.org/japan/Global/japan/pdf/Uequal-impact-en.

pdf downloaded 30 March 2018

Vajda, N., & Kim, C.-K. (2010). Determination of radio-

strontium isotopes: A review of analytical methodol-

ogy. Applied Radiation and Isotopes,68, 2306–2326.

doi:10.1016/j.apradiso.2010.05.013

VanDam, H. (1986). Silver from Chernobyl. Nature,324,

216. doi:10.1038/324216a0

Velasco, H., Cid, A. S., Anjos, R. M., Zamboni, C. B., Rizzotto,

M., Valladares, D. L., & Ayub, J. J. (2012). Variability of

Cs-137 and K-40 soil-to-fruit transfer factor in tropi-

cal lemon trees during the fruit development period.

Journal of Environmental Radioactivity,104,64–70.

doi:10.1016/j.jenvrad.2011.09.016

Wake, D., Brown, R. C., Trottier, R. A., & Liu, Y. (1992).

Measurements of the efficiency of respirator filters

and filtering facepieces against radon daughter aero-

sols. The Annals of Occupational Hygiene,36, 629–636.

Walker, T. (2000). Radioactive decay rate depends on che-

mical environment. CEN Technical Journal,1,4–5.

https://creation.com/images/pdfs/tj/j14_1/j14_1_04-

05.pdf

Wanklyn, A. (2016). Retrieved from https://www.japan

times.co.jp/news/2016/09/23/national/crime-legal/

canada-activist-found-guilty-harassing-scientists-

fukushima-fallout/#.Wem9soVOKUk

Willard, H. H., & Goodspeed, E. W. (1936). Separation of

strontium, barium, and lead from calcium and other

metals—by precipitation as nitrates. Industrial and

Engineering Chemistry,8, 414–418.

Willis, C., Boyd, A. W., & Young, M. J. (1970). Radiolysis of

air and nitrogen–oxygen mixtures with intense

electron pulses: Determination of a mechanism by

comparison of measured and computed yields.

Canada Journal Chemical,48, 1515–1525.

doi:10.1139/v70-247

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 98 of 100

Willis, C., Boyd, A. W., Young, M. J., & Armstrong, D. A.

(1970). Radiation chemistry of gaseous oxygen:

Experimental and calculated yields. Canada Journal

Chemical,48, 1505–1514. doi:10.1139/v70-246

Winkelmann, I., Endrulat, H.-J., Fouasnon, S., Gesewsky,

P., Haubelt, R., Klopfer, L., . . . Wolff, S. (1986).

Ergebnisse Von Radioaktivitätsmessungen Nach Dem

Reaktorunfall in Tschernobyl. Oberschleissheim:

Institut fur Strahlenhygiene, ISH-Heft 99.

Wojtczak, B. A., Andrysiak, A., Gruener, B., & Lesnikowski,

Z. J. (2008). “Chemical Ligation”: A versatile method

for nucleoside modification with boron clusters.

Chemistry—A European Journal,14, 10675–10682.

doi:10.1002/chem.200801053

Wolf, A. (2012). Response to “an unexpected mortality

increase in the United States follows arrival of the

radioactive plume from Fukushima: Is there a corre-

lation?”International Journal of Health Services,42,

549–551. doi:10.2190/HS.42.3.j

Wolfsberg,A.,Dai,Z.,Zhu,L.,Reimus,P.,Xiao,T.,&Ware,D.

(2017). Colloid-Facilitated Plutonium Transport in

Fractured Tuffaceous Rock. Environmental Science and

Technology,51, 5582–5590. doi:10.1021/acs.

est.7b00968

Wood, D. J., & Law, J. D. (1997). Evaluation of the SREX

solvent extraction process forthe removal of Sr-90 and

hazardous metals from acidic nuclear waste solutions

containing high concentrations of interfering alkali

metal ions. Separation Science and Technology,32,

241–253. doi:10.1080/01496399708003197

Wood, G. O. (1981). Respirator canister testing for radio-

iodine. American Industrial Hygiene Association

Journal,42, 570–578. doi:10.1080/

15298668191420297

Xu, S., Cook, G. T., Cresswell, A. J., Dunbar, E., Freeman, S.

P. H. T., Hou, X., . . . Zhang, L. (2016). Carbon, cesium

and iodine isotopes in Japanese cedar leaves from

Iwaki, Fukushima. Journal of Radioanalytical and

Nuclear Chemistry,310, 927–934.

Xu, S., Zhang, L. Y., Freeman, S. P. H. T., Hou, X. L., Shibata,

Y., Sanderson, D., . . . Tanaka, A. (2015). Speciation of

radiocesium and radioiodine in aerosols from

Tsukuba after the Fukushima nuclear accident.

Environmental Science and Technology,49, 1017–

1024. doi:10.1021/es504431w

Xuan, R. C., Yates, S. R., Ashworth, D. J., & Luo, L. F. (2012).

Mitigating 1,3-dichloropropene, chloropicrin, and

methyl iodide emissions from fumigated soil with

reactive film. Environmental Science & Technology,

46, 6143–6149. doi:10.1021/es300388r

Yablokov, A. V., Nesterenko, V. B., & Nesterenko, A. V.

(2009). Atmospheric, water, and soil contamination

after Chernobyl. Annals New York Academic Sciences,

1181, 223–236.

Yamamoto, K., & Okumura, K. (2014). A study of the

generation of U-232 in UO2 and MOX fuels. Journal of

Nuclear Science and Technology,51, 568–573.

doi:10.1080/00223131.2014.882803

Yamamoto, M., Sakaguchi, A., Ochiai, S., Takada, T.,

Hamataka, K., Murakami, T., & Nagao, S. (2014).

Isotopic Pu, Am and Cm signatures in environmental

samples contaminated by the Fukushima Dai-,ichi

Nuclear Power Plant accident. Journal of

Environmental Radioactivity,132,31–46. doi:10.1016/

j.jenvrad.2014.01.013

Yokouchi,Y.,Mukai,H.,Yamamoto,H.,Otsuki,A.,Saitoh,C.,&

Nojiri, Y. (1997). Distribution of methyl iodide, ethyl

iodide, bromoform, and dibromomethane over the

ocean (east and southeast Asian seas and the western

Pacific). Journal of Geophysical Research—Atmospheres,

102, 8805–8809. doi:10.1029/96JD03384

Yoschenko, V. I., Kashparov, V. A., Levchuka, S. E.,

Glukhovskiy, S., Khomutinin, Y. V., Protsak, V. P., . . .

Tschiersch, J. (2006). Resuspension and redistribution

of radionuclides during grassland and forest fires in

the Chernobyl exclusion zone: Part II. Modeling the

transport process. Journal of Environmental

Radioactivity,87, 260–278. doi:10.1016/j.

jenvrad.2005.12.003

Yoschenko, V. I., Kashparov, V. A., Protsak, V. P., Lundin, S.

M., Levchuk, S. E., Kadygrib, A. M., .. . Tschiersch, J.

(2006). Resuspension and redistribution of radionu-

clides during grassland and forest fires in the

Chernobyl exclusion zone: Part I. Fire experiments.

Journal of Environmental Radioactivity,86, 143–163.

doi:10.1016/j.jenvrad.2005.08.003

Youn, D., Patten, K. O., Wuebbles, D. J., Lee, H., & So, C. W.

(2010). Potential impact of iodinated replacement

compounds CF3I and CH3I on atmospheric ozone: A

three-dimensional modeling study. Atmospheric

Chemistry and Physics,10, 10129–10144.

doi:10.5194/acp-10-10129-2010

Yu, W., He, J. H., Lin, W. H., Li, Y. L., Men, W., Wang, F. F., &

Huang, J. (2015). Distribution and risk assessment of

radionuclides released by Fukushima nuclear acci-

dent at the northwest Pacific. Journal of

Environmental Radioactivity,142,54–61. doi:10.1016/

j.jenvrad.2015.01.005

Zachariasen, W. H., & Plettinger, H. A. (1959). Crystal

chemical studies of the 5F-series of elements. 25.

The crystal structure of sodium uranyl acetate. Acta

Crystallographica,12, 526–530. doi:10.1107/

S0365110X5900158X

Zhang, A. Y., Xu, L., & Lei, G. (2016). Separation and

complexation of palladium(II) with a new soft

N-donor ligand 6,6ʹ-bis(5,6-dinonyl-1,2,4-triazin-3-

yl)-2,2ʹ-bipyridine (C9-BTBP) in nitric acid medium.

New Journal of Chemistry,40, 6374. doi:10.1039/

C5NJ03082J

Zhang, W., Friese, J., & Ungar, K. (2013). The ambient

gamma dose-rate and the inventory of fission pro-

ducts estimations with the soil samples collected at

Canadian embassy in Tokyo during Fukushima nuclear

accident. Journal Radioanal Nuclear Chemical,296,

69–73. doi:10.1007/s10967-012-2040-3

Zheng, W., Papiernik, S. K., Guo, M., Dungan, R. S., & Yates,

S. R. (2005). Construction of a reactive surface barrier

to reduce fumigant 1,3-dichloropropene emissions.

Environmental Toxicology and Chemistry,24, 1867–

1874. doi:10.1897/04-488R.1

Zhou, L., Rao, R., Corcoran, E., & Kelly, D. (2016).

Distribution of radionuclides between atmosphere

and ash during combustion of contaminated vege-

tation. Journal of Environmental Radioactivity,165,

159–167. doi:10.1016/j.jenvrad.2016.09.017

Zilberman, B. Y., & Romanovskii, V. N. (2003). Extraction

Studies at the Khlopin Radium Institute.

Radiochemistry,45(3), 211–218. (Translation of

Radiokhimiya, 2003, 45, 193–199). doi:10.1023/

A:1026010706135

Zimmers, T. A., Sheldon, J., Lubarsky, D. A., Lopez-Munoz,

F., Waterman, L., Weisman, R., & Koniaris, L. G.

(2007). Lethal injection for execution: Chemical

asphyxiation? PLOS Medicine,4(4), e156. doi:10.1371/

journal.pmed.0040156

Zinkle, S. J., Terrani, K. A., Gehin, J. C., Ott, L. J., & Snead, L.

L. (2014). Accident tolerant fuels for LWRs: A per-

spective. Journal of Nuclear Materials, (448), 374–379.

doi:10.1016/j.jnucmat.2013.12.005

Zou,Q.,Liu,R.Q.,Ning,S.Y.,Wang,X.P.,&Wei,Y.Z.(2017).

Recovery of palladium by silica/polymer-based 2,6-bis

(5,6,7,8-tetrahydro-5,8,9,9-tetramethyl-5,8-methano-

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 99 of 100

1,2,4-benzotriazin-3-yl)pyridine adsorbents from high

level liquid waste. Journal of Nuclear Science and

Technology,54, 569–577. doi:10.1080/

00223131.2017.1298481

Zundel, W. S., Tyler, F. H., Mays, C. W., Lloyd, R. D., Wagner,

W. W., & Pendleton, R. C. (1969). Short half-times of

caesium-137 in pregnant women. Nature,221,

89–90. doi:10.1038/221089b0

You are free to:

Share —copy and redistribute the material in any medium or format.

Adapt —remix, transform, and build upon the material for any purpose, even commercially.

The licensor cannot revoke these freedoms as long as you follow the license terms.

Under the following terms:

Attribution —You must give appropriate credit, provide a link to the license, and indicate if changes were made.

You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.

No additional restrictions

You may not apply legal terms or technological measures that legally restrict others from doinganything the license permits.

Cogent Chemistry (ISSN: 2331-2009) is published by Cogent OA, part of Taylor & Francis Group.

Publishing with Cogent OA ensures:

•Immediate, universal access to your article on publication

•High visibility and discoverability via the Cogent OA website as well as Taylor & Francis Online

•Download and citation statistics for your article

•Rapid online publication

•Input from, and dialog with, expert editors and editorial boards

•Retention of full copyright of your article

•Guaranteed legacy preservation of your article

•Discounts and waivers for authors in developing regions

Submit your manuscript to a Cogent OA journal at www.CogentOA.com

Foreman, Cogent Chemistry (2018), 4: 1450944

https://doi.org/10.1080/23312009.2018.1450944

Page 100 of 100

Sustainable Solvent Extraction of Gold with Biomass Chemicals

Article

Full-text available

Jan 2024

This paper presents the basis for an industrial gold purification process using an organic phase made from biomass derived organic chemicals is presented. The use of a sustainable kerosene (a biodiesel) as a diluent in a solvent extraction experiment is important as it allows the solvent extraction of metals to be done without petroleum kerosene. A chemical change in the organic phase which reduces the gold distribution ratio has been observed and rationalized with XANES/EXAFS, this change offers path towards more sustainable flowsheets for gold. A second process is also presented using biomass derived diluent, the parameters required to calculate the ratio of the activity functions of chloride and the tetrachloroaurate(iii) complex in choline chloride media are within this paper. Additionally solvent extraction experiments using the new sustainable diluent for lithium and alkaline earth elements together with proof of principle experiments with stable lanthanides, 99mTc, ¹⁵²Eu, ²³⁸Pu and ²³⁹Pu were performed.

Low-temperature fusion using NH4HSO4 and NH4HF2 for rapid determination of Pu in soil and sediment samples

Article

Oct 2018
ANAL CHIM ACTA

Two fusion methods were established for rapid determination of Pu in soil and sediment samples. The methods consisted of NH4HSO4 or NH4HF2 fusion procedures incorporated with procedures for CaF2/LaF3 co-precipitation, extraction chromatography and SF-ICP-MS measurement. The fusion procedures were done on a portable hot plate instead of in a cumbersome muffle furnace and took only 15 min heating-up time from room temperature to 250 °C and 15 min fusion time at 250 °C. Chemical recoveries of Pu after completing the NH4HSO4 and NH4HF2 fusion methods for 0.5–1 g sample were approximately 70% and more than 90%, respectively, and decreased with the increase of sample weight from 0.5 g to 5 g. Sediment samples were pre-ignited at different temperatures ranging from 450 °C to 1000 °C to form refractory fractions of Pu, with which the dissolution rates of Pu by the NH4HSO4 and NH4HF2 fusion were investigated. With the increase of pre-ignition temperature of the sediment samples, the dissolution rates of Pu from the samples prepared by NH4HSO4 fusion declined dramatically from near 100% for 450 °C to 8% for 1000 °C. In contrast, the NH4HF2 fusion was capable of completely releasing Pu from samples that were pre-ignited at temperatures over 450 °C to 1000 °C, which was comparable to releases obtained by the hazardous and time-consuming HNO3-HF digestion, and was superior to the conventional HNO3 digestion. Additionally, because HF is not used in any procedure of the NH4HF2 fusion, a safer and greener alternative to NH4HSO4 fusion and HNO3-HF digestion is realized for rapid Pu determination in environmental samples for nuclear emergency response and application in environmental studies.

Metal extraction from a deep eutectic solvent, an insight into activities

Article

Full-text available

Apr 2020

The solvent extraction of gold, palladium, technetium, indium and rhenium from both mixtures of a deep eutectic solvent with aqueous salt solutions and of two different aqueous salt solutions has been performed. Initially using gold and then the other metals the solvent extraction results were interpreted using an activity coefficient / function equation (Specific Ion interaction Theory). The most important presented result is the addition of a new term to the specific ion interaction theory equation. Using the new model it will be possible to make predictions of the behaviour of a solvent extraction system where one of the liquid phases is a mixture of aqueous salts and the deep eutectic solvent.

Consequences of the radiation accident at the Mayak production association in 1957

Article

Full-text available

Jul 2017

This manuscript presents an overview of the accident that occurred at Production Association "Mayak" (PA "Mayak") (Russian Federation) on 29th September 1957. It gives brief characteristics of the efficacy of the implemented protective measures that made it possible to considerably minimize exposure doses to population. The paper also provides retrospective dosimetry estimates for the members of East Urals Radioactive Trace Cohort (EURTC) which comprises approximately 21,400 people. During the first 2 years after the accident decrease in the group average leukocyte (mainly due to neutrophils and lymphocytes) and thrombocyte count as well as left deviation were observed in the population. At later dates increased excess relative risk (ERR) of solid cancer incidence and mortality was noted in EURTC.

Colloid-Facilitated Plutonium Transport in Fractured Tuffaceous Rock

Article

Full-text available

Apr 2017

Colloids have the potential to enhance mobility of strongly sorbing radionuclide contaminants in groundwater at underground nuclear test sites. This study presents an experimental and numerical investigation of colloid-facilitated plutonium transport in fractured porous media for identifying plutonium reactive transport processes. The transport parameters for dispersion, diffusion, sorption, and filtration are estimated with inverse modeling for minimizing the least squares objective function of multi-component concentration data from multiple transport experiments with the Shuffled Complex Evolution Metropolis (SCEM). Capitalizing on an unplanned experimental artifact that led to colloid formation, we adopt a stepwise strategy to first interpret the data from each experiment separately and then to incorporate multiple experiments simultaneously to identify a suite of plutonium-colloid transport processes. Nonequilibrium or kinetic attachment and detachment of plutonium-colloid in fractures was clearly demonstrated and captured in the inverted modeling parameters along with estimates of the source plutonium fraction that formed plutonium-colloids. The results from this study provide valuable insights for understanding the transport mechanisms and environmental impacts of plutonium in groundwater aquifers.

Recycling of metallic materials from the dismantling of nuclear plants / Wiederverwertung metallischer Stoffe aus stillgelegten Kernkraftwerken

Article

Jun 1991

M. Sappok

Acute nonlymphocytic leukemia, preleukemia, and acute myeloproliferative syndrome secondary to treatment of other malignant diseases. Clinical and cytogenetic characteristics and results of in vitro culture of bone marrow and HLA typing

Article

Apr 1981

Study of the possibility of using Europium and Pyrex alloy as burnable absorber in PWR

Article

Dec 2017
ANN NUCL ENERGY

Ahmed Abdelghafar Galahom

The pursuit for an optimum burnable absorbers (BAs) takes a great interest due to their importance for regulating and control the reactivity of the reactor. MCNPX code is used to simulate the effect of Europium and Pyrex on the neutronic characteristics of PWR and compare it with the conventional burnable absorber. The thermal neutron flux and the power distribution through PWR assembly are analyzed to investigate the effect of gadolinium and europium on it. The PWR assembly is filled in a different fuel burnup process with 2% Gd2O3 and 2% Eu2O3 as integral burnable absorbers (IBAs). Despite the fact that the absorption cross section of gadolinium is larger than europium, the effective multiplication factor in the case of (UO2 + Gd2O3) IBAs rods increases more than that in the case of (UO2 + Gd2O3) IBAs rods. The Pyrex alloy is investigated in the Burnable poison rods (BPRs) to compare its effect on the neutronic characteristics of PWR with the conventional material such as B4C and (Ag-In-Cd). The effect of these materials on the Keff values has been analyzed. Due to the high absorption cross section of ¹³⁵Xe and ¹⁴⁹Sm resulting from the fission process, it was important to study the effect of different BAs materials on their concentration. The ²³⁹Pu and ²⁴¹Pu concentrations resulting from the burning process have been calculated for the suggested BAs materials.

Behavior of radioactive cesium during incineration of radioactively contaminated wastes from decontamination activities in Fukushima

Article

Sep 2017

Large volumes of decontamination wastes (DW) generated by off-site decontamination activities in Fukushima Prefecture have been incinerated since 2015. The behavior of radioactive cesium during incineration of DW was investigated at a working incineration plant. The incineration discharged bottom ash (BA) and fly ash (FA) with similar levels of radiocesium, and the leachability of the radiocesium from both types of ash was very low (<1%). These results are significantly different from those obtained for the incineration of contaminated municipal solid waste (CMSW) reported in earlier studies. The source of radiocesium in DW-FA is chiefly small particles derived from DW and DW-BA blown into the flue gas, not the deposition of gaseous synthesized radiocesium compounds on the surfaces of ash particles in the flue gas as observed in CMSW incineration. This source difference causes the behavior of radiocesium during waste incineration to differ between DW and CMSW.

Denitration of simulated high-level liquid waste by formic acid for the connection of PUREX process with TRPO process

Article

Jul 2017

Denitration of simulated high level liquid waste (HLLW) by formic acid was performed for the connection of Plutonium Uranium Recovery by EXtraction (PUREX) process with trialkyl phosphine oxide (TRPO) process. The concentration of acid, anions and metal ions in solution were monitored under different mole ratios of formic acid to nitric acid and denitration time. Precipitates formed were characterized by Scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and X-ray absorption near edge structure. This work presents a promising strategy for the connection of PUREX process with TRPO process and also provides some new information on the precipitation behavior in denitration of HLLW.

Radioactively-hot particles detected in dusts and soils from Northern Japan by combination of gamma spectrometry, autoradiography, and SEM/EDS analysis and implications in radiation risk assessment

Article

Jul 2017

After the March 11, 2011, nuclear reactor meltdowns at Fukushima Dai-ichi, 180 samples of Japanese particulate matter (dusts and surface soils) and 235 similar U.S. and Canadian samples were collected and analyzed sequentially by gamma spectrometry, autoradiography, and scanning electron microscopy with energy dispersive X-ray analysis. Samples were collected and analyzed over a five-year period, from 2011 to 2016. Detectable levels of (134)Cs and (137)Cs were found in 142 of 180 (80%) Japanese particulate matter samples. The median radio-cesium specific activity of Japanese particulate samples was 3.2kBqkg(-1)±1.8kBqkg(-1), and the mean was 25.7kBqkg(-1) (σ=72kBqkg(-1)). The U.S. and Canadian mean and median radio‑cesium activity levels were <0.03kBqkg(-1). U.S. and Canadian samples had detectable (134)Cs and (137)Cs in one dust sample out of 32 collected, and four soils out of 74. The maximum US/Canada radio-cesium particulate matter activity was 0.30±0.10kBqkg(-1). The mean in Japan was skewed upward due to nine of the 180 (5%) samples with activities >250kBqkg(-1). This skewness was present in both the 2011 and 2016 sample sets. >300 individual radioactively-hot particles were identified in samples from Japan; composed of 1% or more of the elements cesium, americium, radium, polonium, thorium, tellurium, or strontium. Some particles reached specific activities in the MBqμg(-1) level and higher. No cesium-containing hot particles were found in the U.S. sample set. Only naturally-occurring radionuclides were found in particles from the U.S. background samples. Some of the hot particles detected in this study could cause significant radiation exposures to individuals if inhaled. Exposure models ignoring these isolated hot particles would potentially understate human radiation dose.

Feasibility studies on the selective separation of fission palladium(II) by iso Hex-BTP/SiO 2 -P adsorbent from HLLW

Article

May 2017

Aiming at the selective recovery of fission palladium(II) from high-level liquid waste (HLLW), the silica/polymer (SiO2-P)-based isoHex-BTP adsorbent (isoHex-BTP/SiO2-P) was synthesized by impregnating complexing agent isoHex-BTP into the multiporous SiO2-P inert support. The feasibility of separation of Pd(II) from HLLW by isoHex-BTP/SiO2-P was evaluated by batch experiment method. The results showed that isoHex-BTP/SiO2-P exhibited much higher adsorption selectivity for Pd(II) than the other fission products, even Am(III) and Pu(IV) presented in HLLW. The ideal nitric acid concentration for the adsorption of Pd(II) by the adsorbent was shown to be ≥2 mol dm–3. The adsorption of Pd(II) fits well to the pseudo-second-order kinetic model and Langmuir isotherm model. Quantitative Pd(II) desorption was achieved by using 0.5 mol dm⁻³ SC(NH2)2 - 0.1 mol dm⁻³ HNO3 solution.

Solid Cancer Incidence among the Life Span Study of Atomic Bomb Survivors: 1958–2009

Article

Mar 2017

This is the third analysis of solid cancer incidence among the Life Span Study (LSS) cohort of atomic bomb survivors in Hiroshima and Nagasaki, adding eleven years of follow-up data since the previously reported analysis. For this analysis, several changes and improvements were implemented, including updated dose estimates (DS02R1) and adjustment for smoking. Here, we focus on all solid cancers in aggregate. The eligible cohort included 105,444 subjects who were alive and had no known history of cancer at the start of follow-up. A total of 80,205 subjects had individual dose estimates and 25,239 were not in either city at the time of the bombings. The follow-up period was 1958-2009, providing 3,079,484 person-years of follow-up. Cases were identified by linkage with population-based Hiroshima and Nagasaki Cancer Registries. Poisson regression methods were used to elucidate the nature of the radiation-associated risks per Gy of weighted absorbed colon dose using both excess relative risk (ERR) and excess absolute risk (EAR) models adjusted for smoking. Risk estimates were reported for a person exposed at age 30 years with attained age of 70 years. In this study, 22,538 incident first primary solid cancer cases were identified, of which 992 were associated with radiation exposure. There were 5,918 cases (26%) that occurred in the 11 years (1999-2009) since the previously reported study. For females, the dose response was consistent with linearity with an estimated ERR of 0.64 per Gy (95% CI: 0.52 to 0.77). For males, significant upward curvature over the full dose range as well as restricted dose ranges was observed and therefore, a linear-quadratic model was used, which resulted in an ERR of 0.20 (95% CI: 0.12 to 0.28) at 1 Gy and an ERR of 0.010 (95% CI: -0.0003 to 0.021) at 0.1 Gy. The shape of the ERR dose response was significantly different among males and females (P = 0.02). While there was a significant decrease in the ERR with increasing attained age, this decrease was more rapid in males compared to females. The lowest dose range that showed a statistically significant dose response using the sex-averaged, linear ERR model was 0-100 mGy (P = 0.038). In conclusion, this analysis demonstrates that solid cancer risks remain elevated more than 60 years after exposure. Sex-averaged upward curvature was observed in the dose response independent of adjustment for smoking. Findings from the current analysis regarding the dose-response shape were not fully consistent with those previously reported, raising unresolved questions. At this time, uncertainties in the shape of the dose response preclude definitive conclusions to confidently guide radiation protection policies. Upcoming results from a series of analyses focusing on the radiation risks for specific organs or organ families, as well as continued follow-up are needed to fully understand the nature of radiation-related cancer risk and its public health significance. Data and analysis scripts are available for download at: http://www.rerf.or.jp .

Reactor accident chemistry an update

Abstract

Recommended publications

Crystal Structure of AnO2 and Phase Transition at Higher Pressure: A Brief Review

Quantities of actinides in nuclear reactor fuel cycles

An introduction to serious nuclear accident chemistry

Behavior of radioactive cesium during direct melting treatment of decontamination waste with and wit...

Radioactive particles emitted at the 1FNPS accident福島第一原発事故で放出した放射性粒子: Overview of insoluble Cesium...